Study Discovers 72 Genetic Mutations Linked to Hereditary Breast Cancer

As stated by the National Cancer Institute, invasive breast cancer affects 1 in 8 women in the United States and 5-10% of all breast cancers are hereditary, with abnormal genes passed from parent to child. To date, the most well-known gene mutations are BRCA 1 and BRCA 2, which increase the risk of developing breast cancer and make up around 25% of all hereditary breast cancers. Statistics show that by the age of 70, 55-65% of women who have inherited a BRCA 1 gene mutation and 45% of women who have inherited a BRCA 2 gene mutation will likely be diagnosed with breast cancer.

Yet, this data only takes into account a small portion of factors, or rather genes, that play a role in the development of breast cancer.

New studies

In October 2017, two studies conveyed findings of 72 previously uncovered gene mutations that increase a woman’s risk of developing hereditary breast cancer. The studies were conducted by the OncoArray Consortium, an international team that brought together over 500 researchers from more than 300 institutions worldwide. The researchers analyzed data gathered from 275,000 women, of which 146,000 had breast cancer. Since there are 125,950 base pairs in the BRCA1 mutation, they figured that a simple abnormality of the gene could lead to improper function of the proteins, which are responsible for controlling both the structure and function of all the cells within the body. In turn, improper function of the proteins may trigger the disease. The researchers aimed to identify new predisposing factors or risk factors that might provide insight as to why certain types of cancer develop in certain individuals and why some are harder to treat than others.

The researchers took blood samples from all of the women involved in the study and DNA was analyzed at over 10 million sites throughout the genome (the complete set of DNA present in an organism). At the sites, they investigated whether the DNA sequence in the women with breast cancer was any different from that of the women without breast cancer. Due to the fact that the study was quite extensive, the research team could detect even the subtlest differences.

Of the 72 different genetic mutations uncovered, 65 were associated with an increased risk of breast cancer and the other 7 were associated with a heightened risk of developing hormone-receptor-negative breast cancer. “We know that breast cancer is caused by complex interactions between these genetic variants and our environment, but these newly discovered markers bring the number of known variants associated with breast cancer to around 180. Our hope is that in future we will be able to test for these genetic variants in order to inform preventative approaches and treatment for women who may be at a higher risk of breast cancer,” said Georgia Chenevix-Trench, one of the researchers involved in the study.

These findings confirm current understanding of the inherited basis of breast cancer. In addition to identifying new genetic variants, they also confirm precise pattern waves in the genetic variants that help the researchers to better understand why some women are predisposed to breast cancer, as well as what type of genes and mechanisms are involved in the process.

So what could this information mean for future assessment and treatment? Read on to learn more.