Major Study of Genetics of Breast Cancer Provides Clues to Mechanisms Behind the Disease

Source: University of Cambridge

Summary: A major international collaboration of researchers worldwide identified new genetic variants which contribute to the risk of developing breast cancer.

Researchers from all over the collaborated and identified 72 new genetic variants which contribute to the risk of developing breast cancer. Amongst these variants, 65 are common variants that make susceptible to breast cancer and other 7 variants make susceptible to oestrogen-receptor-negative breast cancer ( a subset of cases which do not respond to hormonal therapies). Complex interactions between a large number of genetic variants and our own environment cause cancer. Nearly 70% of the breast cancer cases are estrogen-receptor +ve which means the cancer cells have a specific protein responds to the female sex hormone, Oestrogen. Other cancer cells which lack this receptor are estrogen-receptor ve. The findings were reported in the journals Nature and Nature Genetics.

Genetics of Breast Cancer


Breast cancer risk through inheritance is due to a combination of rare variants in BRCA1 and BRCA2 genes which confer a high risk of the disease and commoner genetic variants confer a low risk. Totally, the genetic data of 275,000 women were analyzed, of which 146,000 were already diagnosed with breast cancer. The researchers were able to make some acceptable predictions of the target genes in most of the cases by combining epidemiological data with other data from breast tissue. And for the first time, they found that these genes are same as those altered genes in breast tumors. These findings are a result of the work done by the OncoArray Consortium, involving 550 researchers from 300 institutions.

Professor Peter Kraft said, “Given the size of these studies, we expected that we would find a lot of new breast cancer risk variants, but the studies tells us a lot more about which genes are involved, revealing many previously unsuspected genes and genetic mechanisms underlying breast carcinogenesis. This should provide guidance for a lot of future research.

Associate Professor Roger Milne said, “These findings may inform improved risk prediction, both for the general population and BRCA1 mutation carriers”, “A better understanding of the biological basis of oestrogen receptor negative breast cancer may lead to more effective preventive interventions and treatments.”

More Information: Kyriaki Michailidou et al, “Association analysis identifies 65 new breast cancer risk loci”, Nature (2017). DOI: 10.1038/nature24284

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