 THERAPY SUPPLEMENT
Experimental vaccine for ovarian cancer boosts the body's antitumor defenses
Australian research turns up AIDS, cancer link
SYDNEY
Persons with AIDS and transplant patients are at a much higher risk than the general population of developing a range of cancers. A new study published in The Lancet suggests a link between a depleted immune system and 20 different types of cancer and could be a breakthrough in the understanding of the causes of the malignancies.
Lead researcher at Sydney's University of New South Wales, Professor Andrew Grulich said the research looked at two groups-those infected with HIV/AIDS and kidney-transplant patients. "Immune suppression is really the only thing they share," he said. "What we found is that the extent of cancer occurrences in these two populations was very similar. Both had increased rates in a wide variety of cancers."
The research analyzed the results of 12 previous studies completed in Australia, United States, Europe, and Canada and involving more than 444,000 people with HIV/AIDS and some 32,000 organ recipients. It found that of the 28 cancers studied, both groups were at a significant risk of developing 20 of them including cancer of the liver, stomach, cervix, eye, lip, mouth, and penis. HIV/AIDS patients were found to be 11 times more likely to develop Hodgkin's lymphoma while those who had undergone a transplant were almost four times more likely to develop the disease.
Grulich said most of the 20 cancers were mostly linked to infection. He said for those cancers not linked to viruses or bacteria, such as breast and prostate cancer, both groups had similar rates to the general population. "Until now, the accepted wisdom was that there were only three cancers associated with HIV-this paper finds that it is more like 20," he said.
Grulich said the findings could overturn the previously held view that some of these cancers were linked to lifestyle risks such as smoking and sexual practices rather than infection. "We believe that the finding points to an immune deficiency and not those other risk factors," he said.
The results could change the way HIV/AIDS patients are treated, he added. "This evidence suggests that immune deficiency is associated with risk of cancer and this suggests we need to maintain people's immune systems at a higher level-and that might mean putting HIV patients on antiretroviral drugs earlier than is currently the case," he said.
Mutated gene zaps pancreas cancer in mice
WASHINGTON
A mutated gene named Bik can shrink or kill tumors in the pancreas of mice, offering hope for one of the deadliest human cancers. The mutant gene named Bik expresses a protein that forces cancer cells to kill themselves, researchers from The University of Texas MD Anderson Cancer Center said. The team even created a more lethal mutant, called BikDD, which spares healthy tissue.
"There are no good options for pancreatic-cancer patients now," said Prof. James Abbruzzese, chair of the MD Anderson department of gastrointestinal oncology.
Two types of mice were treated after they were infected with two aggressive lines of pancreatic cancer, one in a very advanced stage. Infected control mice in both groups died within 40 days without treatment, while at least half those who received the aggressive BikDD mutant gene survived for 14 months with no signs of cancer.
"This vehicle, or vector, is so targeted and robust in its cancer-specific expression that it can be used for therapy and perhaps for imaging" that could lead to early cancer detection, said senior author Mien-Chie Hung, chair of the Anderson Center.
"This looks like a promising approach to gene therapy for pancreatic cancer and we are working to bring it to a clinical trial," added Abbruzzese. He estimated it will take between one and two years to complete US Food and Drug Administration requirements for phase-I clinical trial in humans. The side effects in mice were mild, they said, which is rare for cancer treatments.
Nine out of 10 pancreatic-cancer patients die within five years of diagnosis, one of the lowest cancer-survival rates.
New treatment boosts survival for child leukemia
PARIS
A prototype method of treating infants with a form of leukemia boosts their chances of survival compared with the standard drug regimen, according to a paper published in The Lancet.
In general, children with acute lymphoblastic leukemia have a good chance of survival-about 80 percent today compared with only 10 percent 40 years ago. But this success rate drops significantly to a range of 17 to 45 percent among infants under 12 months.
Dutch doctors carried out a study of 482 infants from 22 countries who were under one year and had been diagnosed with the disease. In addition to receiving the standard drug (prednisone) for acute lymphoblastic leukemia, the children were given tiny doses of drugs usually designed for treating a related form of cancer, acute myeloid leukemia. The key ingredient was cytabarine, which in lab-dish tests has been shown to be highly effective against lymphoblasts, as immature lymphocyte cells are called. At the 38-month followup mark, 260 (58 percent) of the patients who received this "hybrid" treatment were in complete remission.
Meanwhile, a separate study also published in The Lancet highlights new combination chemotherapy for chronic lymphyocytic leukemia, the commonest form of leukemia in the developed world. Institute of Cancer Research doctors in Britain found that fludarabine (Fludara) and chlorambucil (Leukeran), when used together, were no better than fludarabine alone or chorambucil alone in boosting a patient's chance of survival five years after treatment. However, the combination more than tripled the chance that the disease had not progressed by the time of the five-year checkup.
Vaccine may extend remission for ovarian cancer
CHICAGO
An experimental vaccine for ovarian cancer appears to boost the body's antitumor defenses and could be a useful supplementary therapy for patients with this deadly malignancy, according to a study in the Proceedings of the National Academy of Sciences.
The most deadly reproductive cancer, ovarian cancer is often referred to as a silent killer because it is so hard to detect. While most women with the malignancy respond to chemotherapy, 70 percent of patients die of recurrent disease within five years of diagnosis.
This experimental vaccine is not intended to prevent the cancer, but rather to extend a patient's period of remission by boosting their own immune response to the tumor. In a preliminary trial, 18 women with epilethial ovarian cancer who were given the vaccine went 19 months on average without recurrence.
The vaccine also induced patients' antibody and T-cell responses. These induced cells were present in the women's blood six months, and in some cases 12 months, after immunization-suggesting that the series of shots the women received had a long-lasting effect.
Researchers at Roswell Park Cancer Institute in Buffalo, New York, said the results were encouraging and that this or a similar vaccine warranted further study as the basis for immunotherapy for ovarian cancer.
Coffee and exercise may prevent skin cancer
WASHINGTON
Drinking coffee and exercising may prevent skin cancer by killing off cells damaged by the sun's ultraviolet-B (UVB) radiation, said a study of hairless laboratory mice published in the Proceedings of the National Academy of Sciences. The coffee-exercise combination produced a "dramatic" fourfold difference in apoptosis between laboratory mice that did and did not follow the regime, said the researchers of New Jersey's Rutgers University.
Researchers compared UVB radiation effects on groups of hairless mice that drank caffeinated water (the human equivalent of one or two cups of coffee a day); that exercised on a running wheel; that had caffeine and ran; and a control group that had no caffeine or exercise at all. Compared to the control group, mice that only drank coffee showed a 95-percent increase in UVB-induced apoptosis, those that only exercised showed a 120-percent increase, while those that drank and exercised showed an almost 400-percent increase.
"The differences between the groups in the formation of UVB-induced apoptotic cells-those cells derailed from the track leading to skin cancer-were quite dramatic," said Allan Conney, one of the study's authors. The promising results, however, were likely due to "some kind of synergy ... still somewhat of a mystery" which, until better understood, precludes taking the research to "the next level ... human trials," he added.
Cancer risk seen with very low cholesterol levels
CHICAGO
Lowering bad cholesterol (low-density lipoproteins or LDL) is one of the top strategies for preventing heart disease, but taking it too low may raise the risk of cancer. The red flag comes from a large-scale retrospective analysis of 23 studies involving statin drugs such as atorvastatin (Lipitor), pravastatin (Pravachol), and simvastatin (Zocor). More than 41,000 patients participated in the trials.
Researchers were looking at the data to evaluate the side effects of these drugs-specifically whether they damage liver or muscle cells-when they noticed that low LDL levels were associated with an increased cancer risk. They found an extra case of cancer for every 1,000 patients with low LDL levels compared to higher LDL levels.
The finding is preliminary and further studies will be needed to determine whether the malignancy is a side effect of the drugs or a function of low levels of this type of cholesterol, the researchers cautioned.
"This analysis doesn't implicate the statin in the increasing risk of cancer," said lead author Richard Karas, professor of medicine at Tufts University School of Medicine in Boston. "The demonstrated benefits of statins in lowering the risk of heart disease remain clear; however, certain aspects of lowering LDL with statins remain controversial and merit further research."
John LaRosa, an authority on statins at State University of New York, said there was insufficient evidence to suggest that "there is any problem with LDL lowering that outweighs its significant benefits on vascular disease." However, "we must continue to be vigilant in ensuring that its benefits clearly outweigh its risks," he wrote in an editorial printed with the study in the Journal of the American College of Cardiology.
As to the main question of the study, whether the drugs damage the liver and muscle cells, the investigators said they found no link between lowering LDL and liver or muscle irritation. They did, however, find that liver toxicity levels increased with higher statin dosage. Those findings come from records on more than 75,000 patients.
Given those findings, the researchers suggest that moderate-dose therapy with multiple medications including statins may be preferable to high-dose therapy with statins alone.
Loss of genetic shield aggravates lung cancer
PARIS
Flaws in a key gene called LKB1 help lung cancers develop swiftly into dangerous, metastasizing tumors, a paper published in Nature says. LKB1 has previously been identified as helping the body to suppress cancer. Mutations that disabled this gene were found in patients with Peutz-Jeghers syndrome, which boosts the risk of cancer, and in human lung cancers classified as squamous carcinomas.
The telltale variants could help predict how cancer will develop in a patient and also open up pathways for new drugs, according to the study, led by by Kwok-Kin Wong of the Dana Farber Cancer Institute in Boston, Massachusetts.
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