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Saturday, June 22
The Indiana Daily Student

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Genetic test to help in fight against cancer

New diagnosis tool better at predicting chemotherapy effects

A genetic test appears to help predict how well people with a form of brain cancer will respond to standard chemotherapy drugs.\nDoctors from Johns Hopkins University found victims of aggressive brain tumors called gliomas react better to therapy if they have a particular form of a gene that helps the body repair DNA damages. The testing for that gene type could help doctors tailor cancer treatment.\nDoctors said the same gene might play a role in patients' response to treatment for other forms of malignancy, including lymphoma and cancer of the lung, colon, head and neck, according to last week's issue of the New England Journal of Medicine. The study was financed by the National Cancer Institute. Hopkins has licensed the test to Virco Lab Inc. of Baltimore, which plans to make it available next year.\nIn a related editorial on the study, John N. Weinstein, of the National Cancer Institute said cancer treatments have been selected on the basis of tumor type, pathological features, clinical stage, the patient's age and performance status and other non-molecular considerations. The differences in patients, he said, is often a matter of luck.\nPharmacogenomic studies, a relatively new approach to therapy, will inevitably produce benefits such as these for clinical research and standard practice.\nManel Esteller, a doctor from the Center of Oncology at Johns Hopkins and the head of the study, said "Some gliomas have the capacity to resist drugs like carmustine in chemotherapy. The presence of MGMT (methylguanine methyltransferase in these gliomas), a DNA repair enzyme comes in the way of treating cancer. Therefore, when we detect the presence of MGMT, our study aims at altering it so that it doesn't hinder chemotherapy."\nThe test reveals whether the gene MGMT has been chemically changed through a process called methylation. People whose MGMT genes are altered that way respond much better to chemotherapy drugs.\nIn the study, doctors checked 47 glioma patients. Nineteen had the altered form of the gene, and 12 of the 19 had significant responses to chemotherapy. Among the 28 who had the ordinary form of the gene, only one responded to treatment.\nThose with the altered gene lived an average of 13 months longer than the other patients.\n"In particular, about 30 percent of gliomas lack MGMT. Although the literature on this subject is complex, a lack of MGMT appears to correlate with sensitivity to carmustine."\nEsteller said the new drug will not come without cost. \n"From the perspective of the pharmaceutical industry, they have the potential disadvantage of dividing the market for a successful drug, but their larger potential advantages include the discovery of better drugs, elimination of poor candidate drugs early in the development process and dramatic decreases in the size and expense of clinical trials," Esteller said.

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