NEW USE FOR STATINS
Studies say they can cut the risk of breast, lung, and prostate cancer by half
US considers cancer genome project
WASHINGTON
US scientists are considering creating a complete catalogue of genetic anomalies characteristic of cancer in a new effort to combat the deadly disease. The National Human Genome Institute plans to establish the DNA sequence in at least 12,500 samples of tumors, or create 250 genetic maps for each of the 50 most common types of cancer, to be able to compare these maps with those of healthy cells, The New York Times reported.
"With the completion of the Human Genome Project in April 2003, it is now possible to identify the complete universe of genes involved in every type of cancer," said Francis Collins, director of the Human Genome Institute. "That is the intent of this bold new proposal for a Human Cancer Genome Project. Such an inventory will give researchers powerful new ways to prevent, diagnose, and treat every major form of the disease." While the project "is still in its conceptual stages," scientists were looking forward to working in partnership with the National Cancer Institute to explore how this project can be implemented.
Knowing the defects of the cancer cell "points you to the Achilles' heel of tumors," Eric Lander, director of the Broad Institute, an affiliate of Harvard University and the Massachusetts Institute of Technology, told The Times. Lander and Leland Hartwell, a Nobel Prize winner and president of the Fred Hutchinson Cancer Research Center in Seattle, Washington, presented their cancer-genom-study project before a consultative committee of the NCI in February.
The project was likely to cost about US$1.35 billion over the next nine years, but there is no clear indication where this money will come from, the newspaper quoted institute representatives as saying. Many scientists worry that a project of such magnitude could siphon off funds from other, more modest research projects.
Day care appears to prevent child cancer
PARIS
An infant who goes to a day-care center in the first few months of his or her life faces a lower risk of childhood leukemia, a study in the British Medical Journal suggested. The long-term study assessed the health and family background of more than 6,300 British children aged two to 14 years who did not have cancer and 3,100 who had cancer. Of these, 1,286 had acute lymphoblastic leukemia, which accounts for the vast majority of cases of childhood leukemia.
Children with high levels of social activity outside the home had lower incidence of this disease, but especially those who were put in a creche or in a daily toddler group during the first three months of their life. The authors from Britain's Leukemia Research Fund suggest that the apparent protection against leukemia is linked to early exposure to infection, which could prime the immune system. Similar evidence has been found of a link between early infections and risk of type 1 diabetes and allergies.
Statins halve cancer risk
ORLANDO, Florida
Cholesterol-lowering statins also cut the risk of breast cancer by more than 50 percent, lung cancer by 48 percent, and prostate cancer by 54 percent, according to studies bared at the annual American Society of Clinical Oncology conference in Florida in May.
"If our results are confirmed, I think statins will have a significant chemopreventive role in women at high risk for breast cancer," said Vikas Khurana, an assistant professor of medicine at Louisiana University Health Science Center at Shreveport and senior author of one of the studies.
Khurana, however, warned that it was "far too soon" to tell people they should take the drugs "strictly to lower the risk of cancer." "We are not yet ready to recommend statins to those patients who do not have lipid abnormalities and the reason for that is they are not entirely safe," said Khurana. "They need to be monitored."
Statins neutralize an enzyme that regulates the production of chemical substances that play a role at a cellular level in the spread of cancer. Laboratory studies have shown that certain statins can provoke the natural death of these cells.
Researchers compared the use of statins among 556 women who developed breast cancer against 39,865 women that never suffered from the disease. The data were obtained from records between 1998 and 2004 of women cared for by the US Department of Veteran Affairs.
Another study published in the May 26 issue of the New England Journal of Medicine, showed that statins also halved the risk of developing colon cancer. The cancer rate dropped even when the subjects had a family history of cancer or other risk factors, said researchers at the University of Michigan Comprehensive Cancer Center, who ran the test.
The research "helps bring together evidence that statins may have the potential to prevent chronic diseases other than heart disease, and helps us consider ways to study these powerful drugs for more than one purpose," said author Stephen Gruber at the University of Michigan Medical School.
In the study researchers analyzed 1,953 people with colorectal cancer and 2,015 control subjects who did not have colon cancer. Participants were asked to recall every medication they had used for at least five years. Statin use was determined based on questions and validated against prescription records.
The researchers admit they do not know why statins help protect patients against cancer. "Statins also have antiinflammatory properties that might be relevant for cancer. That may explain why they appear to work in other cancers besides colon cancer," said lead author Jenny Poynter, a graduate student at the University of Michigan School of Public Health. However, researchers caution that people should not begin taking statins to prevent cancer. "We are now working to identify those groups who are likely to benefit most," said Gruber.
Researchers find gene to fight liver cancer
HONG KONG
Researchers in Hong Kong have found a gene that can attack cancer cells, giving hope that a cure can be found for liver cancer. A team from Hong Kong University says the DLC-2 "tumor-suppressing" gene is present in healthy people but not in patients suffering from liver cancer.
"We strongly believe that patients develop liver cancer when the gene disappears from their bodies," Irene Ng Oi-lin was quoted as saying in the South China Morning Post. She said drugs could be developed from this to replace the present forms of treatment, which include chemotherapy and liver transplants. "If medicine can be developed to target these genes, the cancer cells will not be able to duplicate and will die massively, which can improve patients' chances of survival," Ng said.
Not far enough
ORLANDO, Florida
Operations to remove gastric cancers are not going far enough to remove lymph nodes where cancer cells can reproduce, reducing the chances of patient survival, a study presented at the annual meeting of the American Society of Clinical Oncology study said.
In three-fourths of surgeries to remove gastric cancers, the recommended number of lymphatic nodules are also not removed, Natalie Coburn of the University of Toronto said. One-fourth of the patients undergoing surgery for cancer of the stomach or esophagus have the recommended number of ganglions removed and analyzed, said Coburn, who directed the research.
A US commission charged with making recommendations for the treatment of cancer determined in 1997 that at least 15 ganglions near the tumor should be analyzed. The examination allows an assessment of the stage of advancement of the cancer so it can be treated appropriately. In Hawaii, where gastric-cancer operations most frequently remove at least 15 nodules, 33 percent of patients are alive five years later, compared with 16 percent in Utah, where six ganglions are removed on average.
Silent killer in sniper's sights
PARIS
Breast cancer, sometimes dubbed "the silent killer" for stealing women's lives, faces a new and powerful weapon discovered by molecular biology. A new drug that blocks a key enzyme involved in DNA repair dramatically slowed the progression of tumors in lab mice, according to research published in Nature in April.
The research targets the genes BRCA1 and BRCA2. Previous work had shown that breast cells that have defects in these genes become tumorous. Women carrying flawed versions of the two genes have up to an 85-percent chance of developing breast cancer by age 70.
The latest work pinpoints an enzyme called poly(ADP-ribose) polymerase (PARP) that helps to fix repairs in the genetic code. PARP's job is to identify breaks in the DNA and bind to the damaged bit of DNA, attracting specialist proteins to the site to make repairs.
A team led by Alan Ashworth, a professor at the Institute of Cancer Research, London, found that lab-dish cancer cells with deficient BRCA1 and BRCA2 were "unexpectedly and profoundly" sensitive to blocking off PARP. If the PARP was inhibited, the cells became so damaged chromosomally that they became unstable and eventually underwent apoptosis.
The team took the idea further by devising a drug that blocks PARP and tested it on mice that had been injected with BRCA2-flawed tumor cells. The treatment severely blocked the cancer's progress among the rodents. But normal cells were largely unaffected by the drug, because they still possessed the correct version of the genes.
Ashworth, who helped discover the BRCA2 gene in 1995, said the PARP inhibitor works by "exploiting a specific deficiency in breast cancer cells--their Achilles' heel."
The next step is to cautiously test the drug on humans. Volunteers will be given the drug to see if it is safe and does not cause side effects, said the institute. If that works, the next step will be to enroll women with BRCA-deficient tumors and test whether the drug works. "If our laboratory findings are confirmed in the clinic, we could dramatically improve the treatment of patients with BRCA1- or BRCA2-associated cancers," said Andrew Tutt, a breast oncologist at London's Guy's Hospital who was on Ashworth's team.
Danger of flying over North Pole
HONG KONG
Airline Cathay Pacific has limited air crews' flights on the nonstop Hong Kong-New York route after it was found that the journey could increase the likelihood of cancer. Airline staff say they have been limited to just two of the ultra-long-haul flights per month since it was found the route exposed passengers and crew to high levels of cosmic radiation when they flew over the North Pole.
Union chiefs said radiation levels increase markedly at 8,000 meters above the pole, and prolonged exposure could be harmful to cell DNA, possibly causing cancers. "If you do two-and-a-half polar flights a month you are in the danger zone," said Becky Kwan, general secretary of the Flight Attendants Union. "At first when we heard about this everybody was worried. But we have had regular meetings [with air officials] and Cathay and guidance from an aviation doctor." However, unions are concerned no such limits have been put on passenger flights. The report said officials felt it unnecessary, as customers do not fly enough to be at risk.
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