Genome Scan of Uterine Cancer Suggests New Tumor Classes

An analysis of the most common uterine cancer suggests the disease should be reclassified into four categories that may help lead to more targeted treatments.

About a quarter of a group of women who would be thought to have a favorable outcome under traditional diagnosis, or 10 percent of all patients, actually have genetic changes suggesting they have a more serious disease and may be in need of more aggressive treatment, according to the research in the journal Nature. A second DNA study of cancer in the New England Journal of Medicine describes almost all the major mutations in acute myeloid leukemia.

The two papers released yesterday are part of the Cancer Genome Atlas project, a U.S. National Institutes of Health effort to discover what changes make a normal cell cancerous and pinpoint more effective treatments. The work may mark the beginning of a shift from organ-based cancer research to gene- based research, said Michael Melner, scientific program director at the American Cancer Society, who wasnt involved in the research.

Whats becoming more and more evident is the potential that we can segment patients not based on the organ system where they have cancer, but the genetic defects the cancer has, he said. There might be lung cancers that are more genetically similar to brain cancers than to other lung cancers, and so they may be more appropriately treated with brain cancer drugs.

The Cancer Genome Atlas is looking at 20 types of cancer to understand the key mutations for the disease, said Richard K. Wilson, the director of the Genome Institute at Washington University in St. Louis. Right now, doctors consider the organ system, take a sample of the cancerous cells, and look at them under the microscope to determine the type.

Previous results from sequencing breast cancer, lung cancer and colon cancer were released last year. The approaches may lead to new therapies and help provide better care for current patients with existing treatments, doctors said.

The most common form of uterine cancer is found in the cells lining the womb, called the endometrium. The National Cancer Institute estimates that almost 50,000 new cases of endometrial cancer will be diagnosed this year in the U.S., and about 8,000 women will die of the disease.

In the endometrial cancer study, researchers analyzed tumors from 373 women to look for changes. Two current categories are used for endometrial cancer: endometrioid and serous. The former type is typically associated with obesity and has a favorable prognosis, while serous cancers usually have poorer outcome.

Serous and endometrioid cancers are diagnosed by pathologists looking under a microscope. However, by looking at the genomic level, yesterdays report found the endometrioid tumors that were most likely to grow and spread shared genetic features with the serous type, including alterations in the number of copies of a gene.

The finding suggests that women whose cancer has abnormal copies of a gene may be better treated by chemotherapy, which is more aggressive, rather than by radiation, after surgery. That hypothesis should be tested in clinical trials before practice is changed, the authors wrote.

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Genome Scan of Uterine Cancer Suggests New Tumor Classes