Montreal Gazette - New test predicts cancer relapse: McGill researchers find link to genes

A group of Montreal researchers and their U.S. colleagues have discovered a new, highly accurate genetic test that can predict whether some women with breast cancer will suffer a relapse.

The test is reported to be superior than an existing test, and has the potential to spare women at a very low risk of relapse of breast cancer from undergoing toxic chemotherapy.

Almost half of all breast cancer patients belong to a group that is considered at low risk of a relapse. These patients are deemed to be estrogen receptor-positive and lymph node-negative. In their case, the cancer has not spread to the lymph nodes.

That's where the new genetic expression test comes in, developed by scientists at the Research Institute of the McGill University Health Centre, along with colleagues from the Dana Farber Cancer Institute and Harvard Medical School.The test analyzes two sets of 29 genes from tumour samples. One set of genes is responsible for uncontrolled cell growth -the very essence of cancer -and the second set involve genetic instability. Thus, if the test results show high expressions of both sets of these genes, the patient would be at a high risk of a relapse.

"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 would be in favour of withholding chemotherapy, and to identify patients in this low-risk group who would benefit from more aggressive treatments," said Alain Nepveu, an MUHC molecular biologist.

"Some of these aggressive treatments can cause premature menopause as well as secondary cancers, so it's important for doctors to have a very good idea of who could benefit from continued therapy," Nepveu said.