It’s a pretty tall order to say that you want to determine the risk of developing breast/ovarian cancer in an entire population, much less a third world population. But that’s exactly what one country is doing, the Bahamas. A pilot study in 2010 by a group of physicians revealed that women in the Bahamas have the highest recorded risk of developing hereditary breast cancer. Approximately 24% of women diagnosed with breast or ovarian cancer, in the Bahamas, were due to an inherited mutation within the genes BRCA1 & BRCA2. This was the highest recorded frequency of BRCA mutations, with the second closest demographic population being women of Ashkenazi Jewish descent(11%).  This study derived from the observation that the average age of diagnosis for women with breast cancer was 42 years old. Breast cancer as a disease, is an age-associated infliction, with the median age of diagnosis in the US at 61 year of age. The early onset of breast cancer within the Bahamian population suggested a genetic component, something inherited within the bloodlines. Mutations within the BRCA genes became the primary suspect.

Global Incidence of Breast cancer by Age

From this study developed a consortium of Physicians, scientists, government officials and advocates who sought to provide further understanding of the frequency of these mutations within the Bahamian population. Although inherited BRCA mutations cannot be prevented from being passed on to future generations, their risk of causing cancer can be minimized with great efficacy though surgical intervention or aggressive surveillance. Therefore, the Bahamas Breast Cancer Initiative Foundation (BBCIF) was developed to further understand the overall risk of breast cancer within the entire Bahamian population, and provide genetic counseling for women with the inherited forms of the mutation. Through government funding, community fund raising and generous assistance from the Komen foundation, women in the Bahamas have gained tremendous insight into their BRCA status. Presently in the Bahamas, every woman who wants it is able to receive genetic testing and counseling for mutations within the BRCA genes to determine their relative risk for breast cancer.

The initial 2 year goal of the BBCIF foundation is to test over 2,400 women for mutations within the BRCA genes, with the hope of testing every woman in the Bahamas. Over 90% of the mutations found within the Bahamian population are of a specific type (IVS13-1G>A), known as an African founder mutation. The fact that this mutation has been previously associated with African American women and women from the African diaspora suggests that this mutation may have been inherited over many generations. This research is set to have significant impact for the population of the Bahamas but may also set a global standard for cancer prevention. It is conceivable that the Bahamian population may serve as a microcosm for the Afro-Caribbean, African American & women residing in Africa. Previously, hereditary breast cancer genetic testing was limited to families with an elevated cancer incidence history. Until now this has been a direct result of the exorbitant cost associated with genetic testing partially due to patents limiting competition. With a recent ruling by the US Supreme Court nullifying patents over human genes, the future of genetic testing looks promising. Hereditary breast cancer mutation analysis is poised to become a standard practice, and may become as commonplace as blood typing. The Bahamas and the BBCIF are setting a trend, and their work will have significant impact on the global epidemic that is Breast cancer.

Do you know your risk?

Photo credit: shewatchedthesky / Foter / CC BY-NC-ND

Earlier this year, Angelina Jolie shocked the world when she revealed that she had undergone surgery to remove both her breast and have reconstructive surgery because of a positive BRCA test. In June the US Supreme Court ruled it was illegal to patent a gene as a direct result of the BRCA test debacle. Over the past year a lot of fuss has been made about the term BRCA test, but exactly what does it mean? The media in general can be a bit misleading when equating a BRCA test to the equivalent of other diagnostic test such as HIV or tuberculosis tests. A positive BRCA test does not mean you have cancer, neither does it mean you have contracted a foreign disease, known as BRCA. Truth be told, BRCA is an essential part of all of us, man woman and child, and plays a very important role in all of our bodies not only in the fight against cancer but as a function of the body’s ability to repair DNA damage.

Believe it or not, we live in a world that is constantly causing us harm. However, the human body is magnificently resilient and repairs this constant damage inflicted upon us every day of our lives. Just like the body is able to repair a wound when you are cut, so can the body repair the microscopic damage caused daily by our environment. One of the most common examples of daily DNA damage is as a result of UV radiation, the sun. As the harmful UV rays destroy our skin, it can mutate the cells within our skin causing repairable harm. Two of the genes responsible for repairing this damage are BRCA1 & BRCA2. These genes play a crucial role in finding and repairing damaged DNA within our bodies, in order to prevent the cells in our body from multiplying with this DNA damage in tact, leading to catastrophic chaos.

Although these genes play a crucial role in repairing DNA damage throughout the body, it was discovered early on that mutations within these genes are frequently found in women with breast and ovarian cancer at a young age. These common mutations that have been discovered in cancer patients, founder mutations, prevent these genes from binding to DNA in order to repair damage being caused in the body. Although these interactions are occurring at a microscopic level they have a significant effect on the entire human body. Exactly why mutations within BRCA1 & BRCA2 lead to breast and ovarian cancer more than any other cancer, is still somewhat a mystery to science. However, these mutations are inherited from parent to progeny and can also cause other types of cancer including prostate, stomach, pancreatic and colon cancer.

What exactly is a BRCA test? With the advancement in technology, science is readily able to detect whether individuals have mutations within these genes that disable their function. With the initial discovery of these genes, science has spent a considerable amount of time deciphering what these mutations mean, and as a result they have estimated that women with mutations within the BRCA1 & BRCA2 genes have a greater than 50% (50-85%) lifetime risk of developing breast or ovarian cancer. That is significantly higher than the overall risk of the general population, which stands at approximately 10%.  A BRCA test detects these specific mutations within women, and estimates the relative risk of developing cancer based upon the frequency of specific mutations in previous cancer patients. And as these mutations are passed down from generation to generation they often coincide with a history of cancer within a family.

The primary reason Angelina Jolie decided to undergo double mastectomy, removal of both her breasts, was not only because she tested positive for a BRCA mutation but because she also had a history of breast cancer within her family, significantly increasing her individual risk. Additionally, by undergoing radical double mastectomy she cuts her risk of developing breast cancer by 90%. Having her ovaries removed would further reduce her risk of developing ovarian cancer. However, these surgical intervention strategies possess life-altering risks and should be discussed under direct advisement of a primary physician.

One final caveat; the world has developed a heightened sense of the significance of BRCA positivity. However, in reality we still do not know everything there is to know about the genes BRCA1 & 2. There are over 500 different types of documented mutations in BRCA1 and over 300 documented mutations in BRCA2. Only small subsets of these mutations have been correlated with causing cancer, we call those founder mutations. These mutations usually congregate in specific demographic populations, with Ashkenazi Jewish women and Bahamian women being two populations with the highest frequency of BRCA mutations.

Photo credit: NCI (Over 500 different types of BRCA1 mutations)

Debated as either the curse of knowing or a preventative cure, BRCA testing has developed as our most advanced weapon in the fight to prevent breast & ovarian cancer. In families of women stricken by this disease, BRCA testing has offered the first defense in ending this curse. As the discovery of these genes is less than 25 years old, our understanding on their impact on society has dramatically evolved. Therefore, over the next 25 years we may develop a treatment strategy that makes BRCA mutation a negligible overall risk for cancer.

Until then, knowing your risk is the first step to preventing cancer.