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June 18, 2002 |
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Browse Archives n Lung n Breast n General n Prostate n Leukemia n Lymphoma n Colon n News/Issues |
Gene test could point to curable lymphoma BETHESDA, Md. -- June 18, 2002 (Cancer Digest) -- Genetic tests may be able to predict which patients with the most common form of lymphoma will be cured with chemotherapy, researchers report in today's New England Journal of Medicine. The research team led by Dr. Louis Staudt of the National Cancer Institute analyzed thousands of genes in lymphoma biopsy samples from patients with a common form of non-Hodgkin's lymphoma called diffuse large B-cell lymphoma (DLBCL) and determined that the activity of as few as 17 genes could be used to predict patients' response to treatment. "We're able to reliably predict the survival of these patients using data from a small number of genes," Staudt said in a prepared statement. "indicating that this technique should be entirely manageable for routine use." DLBCL is the most common type of non-Hodgkin's lymphoma in adults. Approximately 16,000 new cases are diagnosed in the United States each year, and standard chemotherapy for the disease is effective in only 40 percent of patients. Profiling gene expression in patients' tumors may help clinicians decide which patients are suitable candidates for standard therapy and which should consider other options for treatment. The discovery stems from technology developed for the Human Genome Project and uses DNA microarrays, which allow scientists to analyze thousands of genes at the same time to determine which genes are active and which are nonactive at a given time within the cell. For this study, researchers used the Lymphochip, a specialized microarray containing 12,000 DNA spots representing genes active in normal and malignant lymphoid cells. Staudt and his colleagues profiled gene expression in 240 tumor biopsies from patients with DLBCL and identified more than 600 genes whose expression varied significantly between patients who had responded well to treatment and those whose response was poor. Focusing on genes where the difference in expression was most dramatic between the two groups of patients, researchers narrowed the key genes down to 17. From these genes, the investigators created a formula that could be used to predict survival following chemotherapy. Using the formula, Staudt's team was able to predict that among 32 of the 240 patients in this study classified through conventional means as having the poorest prognosis, that four were in fact cured by standard chemotherapy. Being able to predict which patients will do well with chemotherapy is just as valuable to those patients who would not benefit from chemotherapy since these patients could then pursue more aggressive therapies, such as marrow transplantation, earlier when chances of a cure are better. Another value for the genetic tests, Staudt says, is that information from clinical trials of new anticancer drugs may provide researchers with the ability to determine much earlier which patients are likely to benefit most from the new drug. "It makes sense to get the maximum amount of information from patients' valuable participation in clinical trials," he said. "It's a better investment in the research for both doctors and patients." One such clinical trial already under way, will enroll DLBCL patients who have relapsed after standard chemotherapy. Gene expression profiles of the patients' tumors will be determined prior to treatment to understand which patients respond best to the new regimen. |
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