Researchers discover genetic clues that may lead to early detection of breast cancer

Queen’s University researcher Kristan Aronson, along with her former student Anne Grundy and collaborators John Spinelli and Angela Brooks-Wilson in British Columbia, is part of a research team discovering genetic factors that affect breast cancer risk.

The results, published today in Nature and Nature Genetics, increase understanding of which genetic factors are associated with increased susceptibility to breast cancer, and may lead, in combination with other evidence, to improved methods for early detection of breast cancer.

“As part of our research into discovering the causes of breast cancer, with the ultimate aim of preventing new cases, our team at Queen’s, jointly with the British Columbia Cancer Agency, collaborated with researchers around the world,” says Dr. Aronson (Public Health Sciences). “For the new papers in Nature and Nature Genetics, we are pleased that we were invited to contribute our Canadian Breast Cancer Study with participants from Kingston and Vancouver.”

Seventy-two new genetic variants that contribute to the risk of developing breast cancer have been identified by a collaboration involving hundreds of researchers worldwide. Of these variants, 65 are common variants that predispose to breast cancer, and a further seven predispose specifically to estrogen-receptor negative breast cancer – the subset of cases that does not respond to hormonal therapies, such as the drug tamoxifen.

The findings are the result of work by the Breast Cancer Consortium Association, a huge endeavour involving 550 researchers from around 300 different institutions over six continents. They analyzed genetic data from 275,000 women, of whom 146,000 had been diagnosed with breast cancer.

Breast cancer is caused by complex interactions between genetic and environmental factors. The inherited component of breast cancer risk is due to a combination of rare variants in genes such as BRCA1 and BRCA2 that contribute to a high risk of the disease, and hundreds of more common genetic variants that each contribute to only a small risk. The newly identified gene regions nearly double the number that are already known, thereby bringing the number of known common variants associated with breast cancer to about 180.

“These findings add significantly to our understanding of the inherited basis of breast cancer,” says Professor Doug Easton from the University of Cambridge, one of the lead investigators on the study. “As well as identifying new genetic variants, we have also confirmed many that we had previously suspected. There are some clear patterns in the genetic variants that should help us understand why some women are predisposed to breast cancer, and which genes and mechanisms are involved.”

The research was published October 23 in Nature and Nature Genetics.

“We thank the participants in our studies, without whom this research could not be done,” says Dr. Aronson. “We are also grateful to Queen’s for excellent graduate students and research infrastructure in the Division of Cancer Care and Epidemiology, Queen’s Cancer Research Institute. Funding for this work came from the Canadian Institutes of Health Research, and the Canadian Breast Cancer Foundation (now part of the Canadian Cancer Society).”


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