Genetic Test Predicts Breast Cancer Relapse

A gene signature has been discovered that can accurately predict which breast cancer patients are at risk of relapse, thereby sparing those who are not at risk from the burdens associated with unnecessary treatment.

The test analyzes two sets of 29 genes from breast cancer-tumor samples. One set of genes is responsible for rampant neoplasia, which is the very fundamental nature of cancer, and the second set involves genetic instability. When the test results show high expressions of both sets of these genes, the patient would be at a high risk of a relapse.
Scientists at McGill University,(Montreal, QC, Canada), and their US colleagues, used a variety of molecular biology techniques to examine in 12 publicly available gene expression datasets comprising a total of 2,481 patients with breast cancer. The test is reported to be superior to an existing test, and has the potential to spare women at a very low risk of relapse of breast cancer from undergoing toxic chemotherapy.

Clinicians have been faced with the problem that breast cancer cannot be treated with a one-size-fits-all approach. Some cancers respond to specific treatments while others do not. Close to 50% of breast cancer patients belong to a group defined as "estrogen receptor positive/lymph node negative (ER+/LR-)", who are at low risk of relapse. The majority of patients in this group may not require any treatment beyond the surgical removal of their tumor, while a small minority should receive additional treatment.

Alain Nepveu, PhD, coauthor of the study, said, "The added information provided by our test would enable oncologists to identify those at very low risk of relapse, for whom the risk-benefit ratio might be in favor of withholding chemotherapy, and to identify patients in this low-risk group who would benefit from more aggressive treatments". The study was published on February 1, 2011, in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

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