SPECIAL UPDATE
-
Simian Virus 40, Polio Vaccine and Cancer
ARE
OUR GOVERNMENT HEALTH AGENCIES PROTECTING THE PUBLIC
The issues covered in this Lancet article and the
book reviewed pose some terribly disturbing aspects
of science, medicine, government and reality.
The anguish from realizing what has happened and why is particularly unsettling. Then to consider that these issues may
also present us a model that may explain the numerous increasing neurological, autoimmune and cancerous diseases of our time,
including ME, is terrifying.
These issues and their implications could also
trigger government agencies and pharmaceutical
firms to develop strategies to deny the evidence, malign
the scientists and the patient victims. Or even promote psychiatrists to spin theories about unexplained
syndromes, including ME.
Quintero
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE LANCET
31, JULY 2004
Analysis and Interpretation
BOOK: Monkeys, viruses and vaccines
--------------------------------------------------------------
The Virus and the Vaccine: The True
Story of a Cancer-Causing Monkey Virus,
Contaminated Polio Vaccine, and the Millions of Americans Exposed Debbie Bookchin, Jim Schumacher.
A simian virus known as SV40
has been associated with a number of rare
human cancers. This same
virus contaminated the polio vaccine
administered to 98 million Americans
from 1955 to 1963. Federal health
officials see little reason
for concern. A growing cadre of medical
researchers disagree
by Debbie Bookchin and Jim Schumacher
HARVEY
Pass, the chief of thoracic surgery at the National Cancer Institute, in Bethesda,
Maryland, was sitting in his laboratory one spring afternoon in 1993 when
Michele Carbone, a wiry young Italian pathologist who was working as a
researcher at the NCI, strode in with an unusual request. Pass had never before
met Carbone, and had talked to him for the first time, on the telephone, only a
few hours before. Now Carbone was asking Pass for his help in proving a
controversial theory he had developed about the origins of mesothelioma, a
deadly cancer that afflicts the mesothelial cells in the lining of the chest
and the lung. Mesothelioma was
virtually unheard of prior to 1950, but the incidence of the disease has risen
steadily since then. Though it is considered rare—accounting for the deaths of
about 3,000 Americans a year, or about one half of one percent of all domestic
cancer deaths—the disease is particularly pernicious. Most patients die within
eighteen months of diagnosis.
Pass,
one of the world’s leading mesothelioma surgeons, knew, like other scientists,
that the disease was caused by asbestos exposure. But Carbone had a hunch he
wanted to explore. He told Pass that he wondered if the cancer might also be
caused by a virus—a monkey virus, known as simian virus 40, or SV40, that had
widely contaminated early doses of the polio vaccine, but that had long been
presumed to be harmless to people.
[ One of SV40's constituent proteins, large T-antigen: "the most oncogenic protein ever discovered" ]
Pass
listened as Carbone described for him the history of the early polio vaccine. A
breakthrough in the war against polio had come in the early 1950s, when Jonas
Salk took advantage of a new discovery: monkey kidneys could be used to culture
the abundant quantities of polio virus necessary to mass-produce a vaccine. But
there were problems with the monkey kidneys. In 1960 Bernice Eddy, a government
researcher, discovered that when she injected hamsters with the kidney mixture
on which the vaccine was cultured, they developed tumors. Eddy’s superiors
tried to keep the discovery quiet, but Eddy presented her data at a cancer
conference in New York. She was eventually demoted, and lost her laboratory.
The cancer-causing virus was soon isolated by other scientists and dubbed SV40,
because it was the fortieth simian virus discovered. Alarm spread through the
scientific community as researchers realized that nearly every dose of the
vaccine had been contaminated. In 1961 federal health officials ordered vaccine
manufacturers to screen for the virus and eliminate it from the vaccine. Worried
about creating a panic, they kept the discovery of SV40 under wraps and never
recalled existing stocks. For two more years millions of additional people were
needlessly exposed—bringing the total to 98 million Americans from 1955 to
1963. But after a flurry of quick studies, health officials decided that the
virus, thankfully, did not cause cancer in human beings.
After
that the story of SV40 ceased to be anything more than a medical curiosity.
Even though the virus became a widely used cancer-research tool, because it
caused a variety of tumors so easily in laboratory animals, for the better part
of four decades there was virtually no research on what SV40 might do to
people.
Carbone
had reviewed some old research papers on the contamination and some of the
early tests on SV40. He had even reviewed the notes from a crucial 1963
epidemiological study, by Joseph Fraumeni, an NCI researcher, which had
concluded that children inoculated with contaminated vaccine did not show
increased mortality rates. The studies did not impress Carbone: no one had
systematically searched for evidence of the virus in tumors, and, as Fraumeni
himself noted, the epidemiological study was too short to have detected certain
slow-developing cancers. (Mesothelioma can take twenty to forty years to
develop.)
Carbone
had just finished a series of experiments in which he had injected the virus
into dozens of hamsters. Every one of them developed mesothelioma and died
within three to seven months. The results made Carbone wonder if SV40 might
also play a role in human mesothelioma. He had come to see Pass because he had
heard that the senior surgeon had meticulously saved tumor tissue from every
one of the dozens of mesothelioma surgeries he had performed, and now had one
of the largest collections of mesothelioma biopsies in the world. Carbone asked
Pass if he could look for SV40 DNA in Pass’s tumor-tissue samples, using a
sophisticated molecular technique, known as polymerase chain reaction, or PCR,
to extract tiny fragments of DNA from the frozen tissue and then amplify and
characterize them.
As
they talked, Pass became more and more impressed with Carbone. The young
scientist was energetic and extremely self-confident—something Pass attributed
to Carbone’s surgical patrimony. (Carbone’s father is a well-known orthopedic
surgeon in Italy.) When Carbone had finished describing his proposed
experiment, Pass realized that the implications were potentially significant. Only
a handful of viruses have been directly associated with human cancers, and none
of them are simian in origin. If SV40 was linked to mesothelioma in people,
might it also cause bone and brain cancers in human beings, as it had done in
hamsters? What if the monkey virus could spread from person to person? And if the virus was cancer-causing, or
oncogenic, what was one to make of the fact that millions of Americans had been
exposed to it as part of a government-sponsored vaccination program?
“I
thought to myself, He’s got this wild-assed idea,” Pass recalls. “If it’s true,
it’s unbelievable. Even if it’s not, I’m going to get a hell of an education in
state-of-the-art molecular biology.”
Others
at the National Institutes of Health—including some of the scientists who had
been around at the time of the contamination scare—were less receptive to the
novel theory. They told Carbone that the last thing anyone wanted to hear was
that the exalted polio vaccine was linked to cancer. Too much was at stake.
Implicating a vaccine contaminant in cancer—even if the contamination occurred
some forty years ago—might easily shake public confidence in vaccines in
general. And besides, everyone knew that asbestos was the cause of
mesothelioma.
Carbone
sought the advice of two renowned pathologists, Umberto Saffiotti, the chief of
the NCI’s Laboratory of Experimental Pathology, and Harold L. Stewart, a former
director of pathology at the NCI who was once the head of the American
Association for Cancer Research. Both urged Carbone to follow his intuition.
“Forget what people tell you,” Stewart told Carbone. “They told me I was wrong
all my life. If you want to do it, you should, or you will regret it.” That
spring afternoon in 1993, with Pass’s mesothelioma samples in hand, Carbone
called an old friend, Antonio Procopio, a professor of experimental pathology
in Italy who had worked for three years at the NIH. “I asked him if he was
willing to do this crazy project with me,” Carbone says. “I told him I could
not pay him or his expenses.” A month later Procopio arrived in Bethesda. “We
had no money,” Carbone recalls. “He slept in my house for six months, and we
worked day and night.”
It
turned out that Pass’s samples were loaded with the monkey virus: 60 percent of
the mesothelioma samples contained SV40 DNA; the nontumor tissues used as
controls were negative. Moreover, Carbone found that in most of the positive
samples he tested, the monkey virus was active, producing proteins—suggesting
to Carbone that the SV40 was not just an opportunistic “passenger virus” that
had found a convenient hiding place in the malignant cells but was likely to
have been involved in causing the cancer.
In
1994 Carbone, Pass, and Procopio published the results of their experiment in
Oncogene, one of the world’s leading cancer-research journals. They proposed
SV40 as a possible co-carcinogen in human mesothelioma. It was the first time
researchers had put forward hard evidence that the all-but-forgotten vaccine
contaminant might cause cancer in human beings.
MICHELE
Carbone is almost stereotypically Italian: generous with his emotions,
outspoken, and jovial. He is strikingly handsome, with large brown eyes and
shoulder-length brown hair. Carbone grew up in a cultured home in Calabria, on
the shores of the Mediterranean in southern Italy. As a youth he often spent hours poring over medical texts, some
of them 300 years old, in the voluminous library started by the first of the
seven generations of Carbone physicians to date. If his father gave him
science, from his mother he may have inherited the strong intuition that is his
distinguishing characteristic as a researcher. She is an accomplished artist
whose work is exhibited widely in Europe.
Carbone
graduated in 1984, at the top of his class, from the University of Rome Medical
School, one of the largest in the world, and quickly won a coveted NIH doctoral
fellowship. In 1993 he received a Ph.D. in human pathology. In less than a
decade he has risen to the top of his profession. Today he is internationally
recognized as an expert in mesothelioma.
Since
1994 Carbone has written more than twenty studies and reviews investigating
SV40’s link to human cancer. “There is no doubt that SV40 is a human
carcinogen,” he says. “SV40 is definitely something you don’t want in your
body.” Carbone suggests that the virus works in tandem with asbestos or by
itself to transform healthy mesothelial cells into cancerous ones.
Since
he published his first study, scientists at seventeen major laboratories—in the
United States, Great Britain, France, Belgium, Italy, and New Zealand—have
confirmed Carbone’s research with respect to the presence of SV40 in human
mesothelioma. Their results point to a solution to an enigma that long puzzled
researchers. At least 20 percent of mesothelioma victims report no asbestos
exposure, and only 10 percent of people who have had heavy exposure to asbestos
ever develop mesothelioma. The experiments suggest that SV40 may be another
factor at work in the tumors.
Two
very recent studies, from Finland and Turkey, found no SV40 in domestic
mesothelioma samples but did find it, respectively, in American and Italian
samples. The authors observe that their negative findings lend support to the
theory that contaminated polio vaccine is associated with the disease: neither
Turkey nor Finland used SV40-contaminated vaccines. Today Finland has one of
the lowest rates of mesothelioma in the Western world.
The
virus has also been located in other kinds of tumors. More than a dozen
laboratories have found SV40 in various kinds of rare brain and bone tumors. In
1996 Carbone reported that he had found SV40 in a third of the osteosarcomas
(bone cancers of a type that afflicts about 900 Americans a year) and nearly
half of the other bone tumors he tested—research that has since been confirmed
by numerous laboratories. The virus has also been detected in pituitary and
thyroid tumors.
The
possibility of a link between SV40 and brain tumors is particularly intriguing.
Like mesothelioma, brain tumors have become dramatically more common in recent
years. Brain tumors will be diagnosed in about 3,000 children in the United
States alone this year. In 1995 Janet Butel, the chairman of the department of
molecular virology and microbiology at the Baylor College of Medicine, in
Texas, and her chief collaborator, John Lednicky, also a Baylor virologist,
reported that they had found SV40 in a number of children’s brain tumors. Butel
and Lednicky reported that DNA sequencing revealed that the virus was not a
hybrid but rather authentic SV40 -- the same as the SV40 found in monkeys. In
the fall of 1996 an Italian research team, led by Mauro Tognon, of the
University of Ferrara, announced that it had found SV40 DNA in a large
percentage of brain and neurological tumors, including glioblastomas,
astrocytomas, ependymomas, and papillomas of the choroid plexus. The
researchers suggested that SV40 may be a “viral cofactor” involved in the sharp
rise in human brain tumors. Late last year an extensive study undertaken in
China reinforced those results. The study examined sixty-five brain tumors,
finding SV40 in each of the eight ependymomas and two choroid-plexus
papillomas, common brain tumors among children. It also found the virus in 33
to 90 percent of five other kinds of brain tumor examined. The authors, writing
in the November, 1999, issue of Cancer, noted that the virus was actively
expressing proteins.
Recent
research also indicates that SV40 has gained a secure foothold in the human
species. In 1996 Tognon and his collaborators reported that they had also found
the virus in 45 percent of the sperm samples and 23 percent of the blood
samples they tested from healthy people, suggesting that the monkey virus could
spread through sexual contact or unscreened blood products. In 1998 the
presence of SV40 antibodies in human blood samples was reported by Butel, who
tested several hundred American blood samples and found antibodies to SV40 in
about 10 percent of them. Butel’s
laboratory also tested samples from children born from 1980 to 1995 -- decades
after the contaminated vaccine was removed from the market. A surprising six
percent tested positive—offering evidence that the virus may now be spreading
from person to person, including from mother to child.
THE
presence of SV40 in human tumors has been reported on in more than forty
independent research papers. But one molecular study that has had an enormous
impact on the direction of SV40 research and funding was performed not by a virologist,
like Butel, or a molecular pathologist, like Carbone, but by an epidemiologist
named Howard Strickler. Strickler served as a senior clinical investigator in
the NCI’s Viral Epidemiology Branch for many years before he joined the Albert
Einstein College of Medicine, in New York, last winter. He has been
persistently skeptical of any association between the vaccine contaminant and
tumors. Though he is no longer at the NCI, he remains instrumental in the
government response.
In
June of 1996 Strickler published a paper with Keerti Shah, of the School of
Public Health at Johns Hopkins University, in Baltimore, in the journal Cancer
Epidemiology, Biomarkers and Prevention. Strickler and Shah reported that they
had come up empty-handed in their search for SV40 in fifty mesothelioma
samples. Their study and a 1999 British study are the only two published SV40
studies with negative results. These two papers, particularly Strickler’s, are
cited again and again by federal health officials as proof that the dozens of
peer-reviewed papers reporting SV40’s presence in human tumors are unpersuasive
and that a major research effort on SV40 is unnecessary.
[
A schematic diagram of the SV40 virus,
which consists of six proteins ]
Strickler
acknowledges that he has never done PCR himself (Shah was responsible for the
PCR work for their 1996 collaboration), but he challenges the work of other
labs that have found SV40 in human tumors.
“I feel that the data are mixed regarding the detection of SV40 DNA in
human tissues,” Strickler says, citing his own negative study and the British
study. Strickler also points out that when SV40 is found in tumor cells, it
often occurs only at very low levels. Whereas human papilloma virus (HPV),
which causes cervical cancer, can be detected at rates of fifty viruses per
cancer cell, SV40 is sometimes found at a rate of one virus per cell. “I find
it curious that even the laboratories that detect SV40 in the cancers report
that the virus is present at such extremely low levels,” Strickler says. John
Lednicky, of Baylor, counters that HPV is very different from SV40. Strickler
“is comparing an apple with an orange,” he says. “SV40 is known to be far more
tumorigenic than HPV in animals. One copy of SV40 per cell is enough to
transform a cell.”
Several
SV40 researchers have criticized Strickler’s 1996 study and the more recent
British one, saying that they treated specimens in a manner that would not
result in the efficient extraction of SV40 DNA. Bharat Jasani, the director of
the molecular diagnostic unit at the University of Wales, in Cardiff, has found
SV40 in British mesothelioma samples. He recently wrote a lengthy critique of
the two studies that has not yet been published. In this critique Jasani
concludes that the negative results “are explainable by the paucity of the
diagnostic biopsy material used and/or insufficient sensitivity of the overall
PCR methodology used.” Jasani says that Strickler’s PCR technique would have
missed low levels of SV40.
Federal
health officials are understandably concerned that any link between SV40 and
human cancers could frighten people away from the polio vaccine and vaccination
in general. They stress that before SV40 in the polio vaccine can be linked
definitively to cancer, the proposition must clear important scientific
hurdles. Carbone and others must prove that the SV40 they have found is not a
laboratory contaminant. They must demonstrate that SV40 is responsible for the
cellular damage that leads to cancer and is not just a benign “passenger” in
human tumors. And they must show that it was introduced into human beings
through the polio vaccine.
In
assessing the research to date, Strickler is perplexed that the virus has been
found in so many kinds of tumors. In addition to the confirmed research
reporting the virus in more than a half dozen kinds of brain tumors and a
similar number of bone tumors, researchers in new, isolated studies have
reported finding the virus in Wilms tumors, which afflict the kidney, and
adenosarcomas, rare cancers of the uterus. “It’s not likely that a single virus
causes ten thousand different diseases,” Strickler says. “That’s not how it
works.”
These
anomalies have fueled Strickler’s suspicion that many of the SV40 findings in
human tumors may really be false positives resulting from laboratory
contamination. He points out that SV40 is used for cancer research in so many
laboratories around the world that almost any lab involved with tumor assays
could conceivably harbor it. “Is it possible that SV40 is in human tumors and
that SV40 is at some level circulating in the human population?” Strickler
asks. “Could it be true? I can’t exclude the possibility, but the studies to
demonstrate it haven’t really been done, and the data in our hands have been
negative.” Strickler’s former boss, James Goedert, the chief of the NCI’s Viral
Epidemiology Branch, agrees. Although he says he has an open mind about SV40,
he believes that contamination may lie behind the findings of Carbone, Butel,
and others.
In
1997, largely in response to Strickler’s study, the International Mesothelioma
Interest Group set out to determine once and for all if the virus was present
in human mesothelioma samples. The organization asked an internationally known
molecular geneticist, Joseph R. Testa, the director of the Human Genetics
Program at the Fox Chase Cancer Center, in Philadelphia, to oversee a study.
Testa, who specializes in mesothelioma research, confesses that initially he
doubted the idea that SV40 could be found in human mesotheliomas, because he
believed it was well established that asbestos was the cause of the disease.
“I’m a very careful person,” Testa says. “I had a fair amount of skepticism
about it.” But the results of the investigation he led changed his mind. Four
laboratories participated in the tightly controlled study, including Carbone’s.
All four found SV40 in at least nine out of the twelve mesothelioma samples
they tested. Each laboratory’s control samples tested negative, suggesting that
the positive SV40 samples were not the result of laboratory contamination. The
results were published in the journal Cancer Research in 1998.
Strickler
believes that Testa’s study “did not really move the ball forward” in
determining whether contamination lies behind findings of SV40 in human tumors.
He questions Testa’s conclusions. “They are trying to make a large point out of
the fact that results were reproduced,” he says. But according to Strickler,
that such a high percentage of tumors tested positive actually casts doubt on
the study’s reliability and raises the possibility that the labs merely
exchanged contaminated samples. “The prevalence [of SV40-positive samples] was
so high ... that you have no way to make the distinction between
[contamination] and a true positive result,” he says.
Carbone
and some of the other scientists we have interviewed say that Strickler’s
contamination theory is a red herring. “We’ve documented that it is the case
that this virus is present and is expressed in these tumors,” Testa says. “I
think the onus is on [federal health officials] to take this new research into
consideration.” Carbone, not surprisingly, is even more adamant. “The idea that
these tumor samples, tested in laboratories all over the world, were all
contaminated, while all the controls remained negative, is ridiculous,” he
says. “There is no scientific evidence in support of contamination, and plenty
of evidence to the contrary. Moreover, many labs have demonstrated SV40 using
techniques other than PCR.”
Recently
we asked several prominent scientists to evaluate the SV40 studies. George
Klein, at the Karolinska Institute, in Stockholm, who chaired the Nobel
Assembly, and is a longtime expert on SV40, read Testa’s study. His conclusion
was different from Strickler’s. According to Klein, the Testa study is “quite
convincing concerning the association between SV40 and mesothelioma,” and “the
evidence suggests that SV40 may contribute to the genesis of some human tumors,
mesothelioma in particular.”
Carlo
Croce, the editor of Cancer Research and a member of the National Academy of
Sciences, agreed. Not only is it indisputable that SV40 is present in human
tumor samples, he told us, but “it looks like the presence of the virus
contributes to the cause of mesothelioma.”
Janet Rowley, the editor of the journal Genes,
Chromosomes and Cancer and a professor of molecular genetics and cell biology
at the University of Chicago, is a pioneer in the study of chromosome
abnormalities in cancer. Rowley’s groundbreaking research was itself called
into question for years. “People didn’t believe that chromosome abnormalities
had anything to do with leukemia,” she recalled. “It took a long time to break
down that prejudice.” She told us that Carbone had faced the same kind of
doubts that first greeted her. “Everybody had assumed that mesothelioma was
associated with asbestos. One of the important things in medicine is not to let
your assumptions and those generally accepted paradigms obscure the fact that
maybe there’s more.” Rowley believes that Carbone and Testa’s work strongly
implicates SV40 as a causal factor in some mesotheliomas.
CARBONE’S
office is tucked into a quiet second-floor corner of the glass-and-concrete
Cardinal Bernardin Cancer Center, at Loyola University, in Maywood, Illinois.
The center is just a few miles west of Chicago and about ten minutes by car
from Oak Park, where Carbone lives in a stately Frank Lloyd Wright house, with
his wife and two daughters. Carbone
came to Loyola in 1996 after a two-year stint at the University of Chicago. Now
an associate professor of pathology, he works with Paola Rizzo, his senior
scientist and closest collaborator, and a handful of post-docs and lab
assistants in a tidy laboratory just down the hall from his office.
[ The difference SV40
makes: left, chromosomes of a normal mesothelial cell; right, damaged
chromosomes after infection ]
The
lab is lively. Carbone has recruited compatriots as some of his research
assistants, and the whir of high-tech machinery is punctuated by good-natured
banter in Italian. This afternoon Carbone is examining an SV40-infected
cell-culture plate under a microscope. He speaks almost fondly of the virus he
has studied for most of the past decade. SV40 is “the smallest perfect war
machine ever,” Carbone murmurs. “He’s so small. But he’s got everything he
needs.”
Magnified
50,000 times under an electron microscope, SV40 doesn’t seem particularly
menacing. It looks almost pretty—bluish snowflakes, against a field of white.
The virus consists of six proteins, three of which make up the twenty-sided
triangular scaffolding that is the virus’s protein skin. But one of the
remaining proteins, called large T-antigen (for “tumor antigen”), is, according
to Carbone, the most oncogenic protein ever discovered. It is unique, he says,
in its ability to cause cancer when it is set loose inside a cell.
In
1997, in Nature Medicine, Carbone published the first in a series of papers
that outlined how large T-antigen blocks crucial tumor-suppressor pathways in
human mesothelial cells. Whenever a cell begins to divide, in the process known
as mitosis, a small army of quality-control agents goes to work. Running up and
down the cell’s DNA, these genes and proteins work together to scrutinize the DNA’s
integrity. If at any stage of cell division they detect DNA abnormalities that
cannot be repaired, mitosis is halted and the cell undergoes apoptosis, or
cellular suicide. The principal in this elaborate regulatory dance is a gene
called p53. Arnold Levine, the president of The Rockefeller University, in New
York City, and the discoverer of p53, says that 60 percent of all cancers
involve some sort of p53 damage, mutation, or inactivation. “The p53 gene is
central to human cancers,” he says, describing it as “the first line of defense
against cancer formation.”
Carbone’s
experiments have shown that in human mesotheliomas large T-antigen attacks p53,
binding to it so that it cannot function properly. Large T-antigen also
strangles a series of proteins called Rbs, which together serve as some of the
final gatekeepers in cellular division.
No
other cancer-causing virus uses just one protein to knock out two different
regulatory pathways simultaneously. For example, human papilloma virus must produce
two proteins, E6 and E7, to inactivate p53 and the Rbs respectively; SV40 does
its damage in one stroke. Levine calls large T-antigen “a remarkable protein.”
Large
T-antigen’s cancer-causing havoc isn’t limited to disabling a cell’s most
important tumor suppressors. It can also damage chromosomes by adding or
deleting whole sections of DNA or reshuffling the genes. Once the virus is finished with a cell,
Joseph Testa says, “it looks like somebody set off a bomb inside the cell’s
nucleus, because of all these chromosome rearrangements.” Carbone says that
because SV40 binds to tumor-suppressor genes and also causes genetic damage, it
“is one of the strongest carcinogens we know of.”
Yet
he emphasizes that most people who carry SV40 in their cells won’t develop
cancer, because a healthy immune system generally seeks out and destroys
invading viruses. He points out that large T-antigen normally provokes a
particularly strong immune response, unless a person has been exposed to
asbestos, a known immunosuppressant. “Human beings,” Carbone says, “have
devised many mechanisms to defend themselves against cancer. This is one of the reasons that human beings
live so long compared with other animals. Human cancer is usually the result of
a number of unfortunate events that together cause a malignant cell to emerge.”
But
SV40 may have evolved other strategies to elude the immune system. In a recently published article Carbone
writes that sometimes SV40 produces such small amounts of large T-antigen that
the virus escapes detection. Paradoxically, in this hypothesis small amounts of
the virus are even more dangerous than large amounts.
Other
scientists suspect that SV40 can inflict damage and then disappear completely,
in what is described as a “hit-and-run” attack. This analogy is lent credence
by a recent German study in which rat cells were infected with SV40 and
transformed into cancer cells. When scientists searched for large T-antigen, it
was no longer present in some of the cells. Further, these cells appeared to be
even more malignant than those that were still expressing the protein, because
the immune system could no longer recognize them as a threat.
The
new theory may explain how SV40 and perhaps other viruses can induce cancer and
yet not be readily detectable once tumors start proliferating rapidly. But that
notion runs counter to traditional scientific thinking about cancer. “As a
geneticist, I would like to see every single cell have evidence of the virus,”
Testa says, noting that the hit-and-run theory must still be proved. But, Testa
observes, “This is an area that’s going to perhaps establish a new paradigm.”
Although
Carbone’s T-antigen research has bolstered his contention that the SV40 found
in human tumors is not simply a passenger virus, until recently he had no
answer to a criticism commonly voiced by those skeptical that the polio vaccine
could be linked to cancer: some of the SV40 he and others have isolated in
human tumors has a crucial genetic difference from the virus that contaminated
the polio vaccine. The SV40 that its discoverers isolated from the polio
vaccine in 1960 had a genetic feature that allowed it to replicate more quickly
than the SV40 subsequently found in human bone and brain cancers and in most
monkeys. That led some to question the
idea that the SV40 that researchers were finding in these tumors was related to
the SV40 in the polio vaccine.
To
settle the issue Carbone sought to examine old vaccine stocks. He was told by
government and drug-company officials that they had thrown out all the old
lots. Then, two years ago, Carbone found an elderly Chicago-area physician who
had an unopened case of polio vaccine from 1955, which he had stored in his
refrigerator for more than forty years.
“I would have gone all the way to Alaska to find this stuff, and here it
was three miles away,” Carbone says. Last summer Carbone finally completed
tests on the vintage vaccine. He found that the tiny vials contained SV40
genetically identical to the strains found in human bone and brain tumors and
in monkeys. “This proves that the SV40 that was present in the polio vaccine is
identical to the SV40 we are finding in these human tumors,” he says. Why was
the SV40 isolated from the 1960 vaccine the faster-growing version? Because,
Carbone says, both kinds occurred in the monkey kidneys used to grow the
vaccine. Carbone and Janet Butel say that the SV40 that grew more quickly might
have had an advantage in cell cultures—perhaps explaining why it was the strain
originally isolated from the vaccine. However, the slower-growing virus would
almost certainly have an advantage in tumor formation, because it would be less
likely to be detected by the immune system.
Because
he believed that the slower-growing SV40 was more likely to induce tumors, Carbone
wanted to see if federally mandated vaccine-screening tests for viruses were
adequate to detect it. Vaccine manufacturers are not required to use
state-of-the-art molecular techniques—PCR, for example—for virus detection.
Instead they rely on ordinary light-microscope examination to look for evidence
of cellular damage by viral contaminants after fourteen-day cycles in tissue
culture. Although the current screening protocols—themselves forty years
old—are, according to Carbone, more than adequate to detect the faster-growing
form of SV40, his tests found that the slower-growing SV40 took at least
nineteen days to grow out, and thus wouldn’t be detected in the fourteen-day
screening cycles. Carbone says his experiments suggest that any slow-growing SV40
present in the vaccine after the early 1960s could have gone undetected.
Carbone
recently tested six vials of polio vaccine manufactured in 1996, and found that
they were negative for SV40. He concludes that the colonies of monkeys used
today must be free of the virus, because if slow-growing strains were present,
the tests used for routine screening would not detect them. (Today’s injected
vaccine is produced on monkey cell lines, and is therefore free of any viral
contaminants, whereas the oral vaccine is still produced on actual kidneys.
Under Centers for Disease Control regulations that went into effect last month,
American children should now receive only injected vaccine.) In a paper on his
tests of vaccines Carbone recommends conducting extensive molecular testing of
polio-vaccine stocks from the 1960s, 1970s, and 1980s to look for the
slower-growing SV40. The issue is more than academic: the results would help to
establish whether SV40 is present in young children today as a result of
continued exposure to contaminated vaccine or as a result of human-to-human
transmission based on the original, 1955-1963 exposure.
DESPITE
the accumulating evidence of SV40’s association with human tumors, the NCI has
been preoccupied with determining whether the virus is even present in human
tumors. For more than two years the NCI’s chief focus with respect to SV40 was
the design and administration of a multi-laboratory study whose stated purpose
was to assess whether PCR was a reliable tool for identifying the presence of
SV40 in human tissue. Critics of the study, including scientists at some of the
participating labs, worried that other agendas were involved. The study was
directed by Howard Strickler and overseen by James Goedert. Nine labs
participated in the study, including those of Keerti Shah, at Johns Hopkins;
Bharat Jasani, at the University of Wales; and Janet Butel, at Baylor, but not
Carbone’s. The study, which was planned and administered by the NCI’s Viral
Epidemiology Branch, had a fairly unusual design. Instead of just seeing whether different labs could replicate one
another’s work, as is usually done, the labs were asked to prove that they
could replicate their own work. Each lab was given a variety of samples from unidentified
human mesothelioma tissues and asked to see if it could find SV40 DNA. Then it
was asked to find SV40 DNA again in masked samples from the same tumor tissue.
We
asked Richard Klausner, the director of the NCI, about his views on SV40 and
about the design of the experiment. Klausner said that the research to date
hadn’t quelled his doubts that SV40 is present in human tumor tissue, and he
questioned the reliability of the techniques that Carbone and others have been
using. “These sorts of molecular technologies are wonderful tools but very
complicated and sometimes misleading to use,” Klausner said. “I think there is
very good reason to question whether there has been the development of adequate
standards or probes, PCR probes,” for detecting the virus.
Like
Strickler and James Goedert, Klausner raised the possibility of contamination
to explain the positive findings of dozens of laboratories. “I do not see any
compelling molecular data” to support the association of SV40 with human
tumors, he told us. “In the absence of compelling clinical or epidemiological
data, it’s very difficult to say this looks like a pressing problem.” We asked
him about the many molecular studies, from numerous independent laboratories
around the world, that had identified SV40 in human tumors. “There’s too much
irreproducibility and too many good explanations for artifact,” he said. Klausner told us that the NCI has taken “an
open approach but a critical one” to the notion that SV40 is associated with
human tumors, and he insisted that it is seriously studying the issue. Michele
Carbone’s work, for instance, has been funded by the NCI. (Carbone is also
funded by the American Cancer Society.)
We
asked Klausner to explain why the Viral Epidemiology Branch had directed the multi-laboratory
molecular-biology study, especially given that neither Strickler nor the head
of the branch, Goedert, has a strong background in the field. Why hadn’t he
tapped an NCI division with more expertise in DNA extraction, sequencing, and
characterization? “Their expertise in viruses and virus-associated disease
makes [the Viral Epidemiology Branch] really the right place to do it .... As
an expert in doing this sort of work, I feel that I can make that decision and
I feel very comfortable with the decision,” Klausner said. “What we are trying
to do is establish some agreed-upon probes and standards that independent
laboratories could utilize to provide ways of either validating or not
validating molecular findings.”
On
another issue, Klausner referred to an epidemiological study that Strickler had
done to determine whether SV40 was linked to human cancer. That study appeared in 1998 in the Journal
of the American Medical Association, and received extensive publicity upon its
release. It concluded that the NCI’s database on cancer incidence shows no
statistically significant correlation between exposure to SV40-contaminated
vaccine and rates of cancer, including rarer cancers such as mesotheliomas,
ependymomas, and osteosarcomas.
Strickler
did find elevated cancer rates among those exposed to SV40, including a
threefold increase in mesothelioma. Susan Fisher, an associate professor of
epidemiology and biostatistics at Loyola, says that although the correlation
Strickler found did not achieve statistical significance, it was at least
“scientifically interesting.” Strickler’s study was “technically correct,”
Fisher says, but “it’s hard to look at these numbers and turn around and say
there is no evidence to suggest an association.”
Moreover,
Fisher says, standard epidemiological techniques may be useless in determining
whether SV40 exposure is linked to higher cancer rates. If the research of
Janet Butel and others is correct and SV40 is now spreading among human beings,
it may be impossible to assemble an experimental group that has never been
exposed to SV40.
The
multi-lab NCI study concluded with six of the nine laboratories detecting SV40
in some samples. However, only two of the labs got the same positive results on
samples from the same tissues. Although the multi-lab study was completed at
the end of 1998, at the time this article was written it had yet to be
submitted for publication.
Memos
sent to Strickler by some of the participating laboratories show that from its
inception the study was plagued by considerable internal strife. (Participating
laboratories we approached declined to share the memos or discuss them. We
obtained them independently.) Two laboratories suggested that poor
DNA-extraction techniques by the outside laboratory Strickler had chosen to
provide the DNA samples were to blame for the largely negative results
obtained. Their concerns were heightened when it was learned that the
contractor had contaminated some of the negative controls.
They
also complained that Strickler was wrongly using the study to imply that
previous positive findings were caused by contamination. “It cannot be that all
of these laboratories are contaminated and that contamination always happens in
mesotheliomas, osteosarcomas and brain tumors, while the negative controls are
always negative,” a scientist from one of the laboratories wrote Strickler.
“Contamination is a random event .... [The] flaws and unresolved scientific
issues ... have become so cumulative as to outweigh any positive scientific benefit
which might be derived from the publication of this study.” From another
laboratory came this objection: “We feel that our comments about data
interpretation are being dismissed and ignored. Your intransigence about the
interpretation of the data and the conclusions of the study have forced us to
admit that the collegiality and the scientific collaboration that was the basis
of this study is very strained.” Both laboratories maintained that Strickler’s
draft manuscript summarizing the study results was wrong in asserting that
contamination was the cause of previous SV40 findings.
An
unlikely ally in the laboratories’ cause has been William Egan, the acting head
of the Food and Drug Administration’s Office of Vaccines Research and Review.
Egan believes there is no strong epidemiological proof that SV40 is associated
with human cancers and emphasizes that the current polio vaccine is free of
SV40. However, he says, there is evidence that the virus may well be present in
some tumor samples. After he had reviewed Strickler’s draft manuscript, last
February, Egan wrote a lengthy letter to Strickler criticizing it. “I think
that this paragraph, and the following paragraph, imply, unintentionally so,
that the positive results [of SV40 in tumors] that have been reported are due
to laboratory contamination; I do not think that this should be implied.”
Strickler responded, “This study would not have been conducted if there was not
some doubt. That point must be made and made clearly.”
Later
Egan chided Strickler about another section of his draft, which stated, “This
multi-institutional study failed to demonstrate the reproducible detection of
SV40 in human mesotheliomas.” Egan wrote, More exactly, it failed to
demonstrate SV40 sequences in this set of mesotheliomas. This is not
inconsistent with SV40 being found by others previously. Indeed, the fact that
laboratories that previously found SV40 in their samples do not now find SV40
in these samples (and get the study controls correct) only lends credence to
their previous findings .... These laboratories are able to find SV40 when it
is there, and do not find it when it is not there.
Frustrated
by continuing objections, Goedert and Strickler considered publishing the study
without the approval of the dissenting labs, but that plan was dropped. Last
September an independent arbitrator was called in to rewrite Strickler’s
manuscript. The dissenters apparently gained some ground. The arbitrator made
major changes in its tone and conclusions. The study now states that “laboratory
contamination was unlikely to have been the source of SV40 DNA”found in human
tumors in previous experiments (by Butel, Jasani, and the other participating
labs).
THIRTY
miles north of Venice, in the seaside resort town of Lignano Sabbiadoro, 200
clinicians and researchers are gathered at the international Conference on
Malignant Pleural Mesothelioma. At a similar conference in Paris five years ago
Carbone startled his audience when he presented his first SV40 paper.
Today
a significant portion of the conference is devoted to SV40’s association with
mesothelioma—testament to a sea change among researchers regarding the simian
virus. Brooke Mossman, the director of the environmental-pathology program at
the University of Vermont, was the first scientist to tease out the complex
molecular pathways by which asbestos disrupts cellular regulatory mechanisms
and causes mesothelioma. She has been impressed by Carbone’s work. At Lignano
she and Carbone are co-chairing a panel on the molecular pathways employed by
asbestos and SV40 which lead to tumor development. In another presentation
Luciano Mutti, a researcher at the Salvatore Maugeri Foundation’s Institute for
Research and Care, in Pavia, will report that mesothelioma patients who test
positive for SV40 have a shorter life-span than those who test negative.
At
the moment the floor belongs to David Schrump, the new chief of thoracic
surgery at the NCI. Schrump matter-of-factly announces the results of a series
of experiments he has just completed. When he “turned off” SV40 large
T-antigen, he says, human-mesothelioma cell cultures that contained the virus
stopped proliferating and started to die. Schrump explains that he undertook
the experiment partly because he was skeptical of SV40’s role in the
development of mesothelioma. He and his team assembled human mesotheliomas that
tested positive for SV40 and then devised a genetic bullet, a strand of RNA
called an “antisense,” which would prevent the expression of SV40 large
T-antigen.
Within
days after the antisense was administered to the cancer cultures, Schrump
found, the growth rates of mesotheliomas with SV40 in them dropped
dramatically; the negative controls were unaffected. One important finding was
that even very low levels of SV40 appeared to be biologically important—a
discovery that speaks to Strickler’s objection about the low levels of SV40
often found in tumor tissue. Schrump’s
study was published late last year in Cancer Research.
Another
study in that same issue also supports the idea that SV40 is actively involved
in mesothelioma. Adi Gazdar is a professor of pathology and the deputy director
of the Hamon Cancer Center, at the University of Texas Southwestern Medical
Center. He originally doubted Carbone’s work on SV40. “Here’s a monkey virus
suddenly popping up in a rare tumor—I was skeptical of the data,” he told us.
So Gazdar devised an experiment that could determine at one stroke whether the
SV40 found in tumors was a lab contaminant and whether the virus is involved in
tumor formation. Gazdar used a technique called laser microdissection to
separate cancerous cells from nearby noncancerous ones. He found SV40 in more
than half of the mesothelioma tumors. He also found the virus in some adjacent
pre-cancerous cells. Significantly, 98
percent of nearby noncancerous cells tested negative for SV40. “That rules out
any contamination,” Gazdar says, “because if a specimen was contaminated, the
SV40 would be in all parts of the specimen—it wouldn’t be localized to the
mesothelium alone.” Moreover, Gazdar says, his study “suggests that the virus
is in the right type of cells many years before they become malignant”—evidence
that SV40 contributes to the development of cancer. Gazdar says of Carbone’s
work, “I feel everything he’s said, I’ve been able to confirm, and more.”
Gazdar
and other scientists believe that the time has come for a major federal funding
initiative on SV40 to better understand who is infected, how the virus works,
and what might be done to prevent disease. “There’s still a lot we don’t know
about the basic biology of this virus in human infections, including what
tissues it infects, how it is transmitted, and when people become infected with
it,” Janet Butel says. “Until more studies are done, we don’t know if we’re
looking at the only types of cancers that have an association with SV40,” she
says of the lung, bone, and brain cancers with which SV40 has been associated
most often. “Maybe these are just the ones we’ve recognized so far. There may
be others people haven’t run across.” Gazdar says, “It’s such a crucial
issue. Possibly millions of people are
sitting with this virus in their mesothelium or other tissues and are at risk
for developing cancers.” Cancers that were once rare “may suddenly become not
so rare,” he says.
“I
think it’s an enormous potential health problem.”
Arnold
Levine, of The Rockefeller University, is not convinced that the virus causes
cancer in human beings, but he, too, believes that the discovery of SV40 in
human tumors warrants a serious federal response. “If it’s part of the cause of a disease,” he says, “it has a
significance in public health and I think we ought to find that out. That’s a good reason to spend taxpayers’
money: to do science to find out whether the public health is really monitored
here properly. I think that maybe there’s enough evidence in the literature now
that the National Cancer Institute ought to put out an RFA.” The reference is
to a Request for Applications, the formal process by which the federal agency
identifies a major health-research initiative and invites scientists to apply
for research funds. “That would stimulate people to come in and design
experiments and replicate these things.” Carbone made the same suggestion to
federal health officials in 1997 but was rebuffed.
Like
the NCI, the Atlanta-based Centers for Disease Control maintains a stance of
neutrality with undertones of skepticism. In a four-page fact sheet called
“Questions and Answers on Simian Virus 40 (SV40) and Polio Vaccine” the CDC
notes that SV40 has been found in some tumors and adds that “more research is
needed” to confirm a causative link with human disease. It also raises the
possibility of contamination as an explanation. It cites Strickler’s work by
name but not that of Carbone, Butel, or Testa.
Some
researchers plan to conduct screenings for the virus. Joseph Testa hopes to
initiate a screening program at Fox Chase’s new cancer-prevention pavilion that
focuses on asbestos exposure. He is collaborating with officials from the
Asbestos Workers Local 14, in Philadelphia, to identify people who are
particularly at risk. Carbone applauds that effort. “If you test positive for
this virus, you should not be anywhere near asbestos,” he says. Bharat Jasani,
who has found SV40 DNA in a high percentage of the British mesotheliomas he
examined, has begun testing British and Canadian mesothelioma patients, at
their request. He hopes they may be candidates for future SV40-targeted therapy.
Last
year scientists reported that a vaccine they had developed targeting large
T-antigen appeared to help prevent and reverse tumors expressing large
T-antigen in mice. Carbone and Harvey Pass, who is now the chief of thoracic
oncology at the Karmanos Cancer Institute, at Wayne State University, in
Detroit, are collaborating with Martin Sanda and Michael Imperiale, of the
University of Michigan at Ann Arbor, who are among the vaccine’s developers.
They hope soon to bring the experimental vaccine to Phase I clinical trials, in
which it will be tested for its safety in human beings, though not yet for
whether it works. Even if the vaccine eventually proves effective in human
beings, years may well pass before it is widely available.
In
an age of uncontrolled AIDS in Asia and Africa, rampant tuberculosis in Russia,
and antibiotic-resistant microbes in American hospitals, does SV40 really
warrant a significant public-health response? There is no doubt, Carbone says,
that the virus is linked to some cancers. What’s more, millions of Americans
now have been exposed to the virus. Studying SV40 may teach us something about
the dangers of cross-species infection at a time when the use of animal tissue
for medical purposes is gaining acceptance.
Good
science is ultimately about the exchange of ideas unfettered by
presuppositions. Sometimes great breakthroughs come out of theories that at
first seemed heretical or even nonsensical. “Can you think of anything more
different on earth than asbestos and a monkey virus?” Carbone says. “Yet you
stick them together and they work together to be more deadly than either one of
them is alone.” He goes on, “This research is important in so many different
ways. It’s not just about SV40 and mesothelioma. It helps us understand the
whole picture of how viruses interact with environmental carcinogens. This
research can help us understand how completely unrelated carcinogens can work
together in causing disease—a mystery we have barely begun to unravel.”
---------------------------------------------------------------
Debbie Bookchin specializes in health and political
issues. Her articles have appeared in The New York Times, The Boston Globe, and
The Nation.
Jim Schumacher is a freelance writer who lives in
Vermont. His articles have appeared in Boston magazine, The Boston Globe, and
Newsday.
------------------------------------------------------------------------
Illustrations by Giacomo Marchesi.
The Atlantic Monthly; February 2000; The Virus and
the Vaccine - 00.02
Volume 285, No. 2; page 68-80.
Copyright
© 2000 by The Atlantic Monthly Company. All rights reserved.
http://www.theatlantic.com/issues/2000/02/002bookchin.htm
_____________________________________________
“They told
Carbone that the last thing anyone wanted to hear was that the exalted polio
vaccine was linked to cancer. Too much was at stake.”
“ vaccines might also be a huge, inadvertent,
uncontrolled experiment in interspecies viral transmission”
“ the government would have to admit that it should have acted sooner to protect public health.”
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
“ now a major journal,
Lancet, has published clear evidence that contaminated polio vaccine is
responsible for up to half of the 55,000 non-Hodgkin's lymphoma cases per
year.”
“This should outrage nearly anyone that reads this. We
trusted these experts to provide us with protection from polio and instead they
planted the seeds of a deadly cancer that would kill over 20,000 a year in the
US.”
Dr Joseph Mercola
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
See these pages
Herpes Virus and
Myalgic Encephalomyelitis
Myalgic
Encephalomyelitis Home Page
The Virus and The Vaccine http://www.oocities.org/sezar99q/TheVirus-Vaccine.html
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