In 2013, Angelina Jolie, the American actress, filmmaker and humanitarian, and receiver of numerous awards, made the difficult decision to undergo a preventative double mastectomy. Two years later, Jolie underwent another preventive surgery—this time, her ovaries and fallopian tubes were removed. Jolie lost her mother, grandmother and aunt to cancer. A simple blood test revealed that Jolie carries the BRCA1 gene mutation, giving her an 87 percent risk of developing breast cancer and a 50 percent risk of developing ovarian cancer. Learning this, Jolie took her health into her own hands.
With an estimated 25 000 Canadian women being diagnosed with breast cancer in 2015, breast cancer continues to be the most common cancer among Canadian women and the second leading cause of death from cancer. Choosing to undergo preventive surgery is not a light decision; however, a woman’s lifetime risk of developing breast or ovarian cancer greatly increases if she inherits a harmful mutation in BRCA1.
There is a common misconception that women “inherit the BRCA1 cancer gene” and that this will eventually cause a woman to develop cancer. Contrary to this belief, we need the BRCA1 gene. This gene produces proteins that help repair damaged DNA and ensures the stability of our genetic information in our cells. However, when this gene is mutated and the protein is not produced or is not functioning properly, DNA damage may not be repaired properly causing the genes in our cells to accumulate more changes that can lead to cancer.
Although 55-65 percent of women who inherit a harmful BRCA1 mutation will develop breast cancer and approximately 39 percent will develop ovarian cancer, testing positive for this mutation does not reveal that an individual will certainly develop cancer; it reveals only that they are at an increased risk. It is important to remember that other characteristics of a women can increase or lower one’s cancer risk, such as one’s reproductive history and physical activity levels. Still, less than half of breast cancer cases can be explained by well-established risk factors. Ongoing cancer research efforts here at Queen’s University will hopefully allow us to understand and treat this disease better, and eventually improve our chances for preventing this disease.
This article was written by Carmen Chan, a MSc candidate in the Department of Public Health Sciences at Queen’s University, and a Canadian Cancer Society Research Information Outreach Team (RIOT) member.