How BRCA Genes Work

That's a breast cancer cell as captured by a scanning electron microscope, which produces a 3-D image.
That's a breast cancer cell as captured by a scanning electron microscope, which produces a 3-D image.
Image courtesy Bruce Wetzel and Harry Schaefer)/The Web site of the National Cancer Institute

Thanks to a 2013 New York Times op-ed, we all know about Angelina Jolie's decision to have a preventive double mastectomy to reduce her risk of developing future breast cancer. Her candid comments revealed that she has both a strong family history of the disease and, based on the results of genetic testing, a mutated form of the gene known as BRCA1, which gives her an 87 percent chance of breast cancer and a 50 percent chance of ovarian cancer [source: Jolie]. Faced with this reality, which can be more or less severe for different people, she chose to remove both breasts before the cells making up her milk-producing glands could turn into rogue cancer cells capable of uncontrolled growth.

If the procedure protects her from this disease, as probability suggests, she'll have lots of people to thank: the genetic counselors, the surgeons, and her family, of course, to name a few.

Mary-Claire King may not make that list. A professor of genome sciences and medical genetics at the University of Washington, King helped to unravel the genetic basis of inherited breast cancer. Her work led first to the discovery of BRCA1 in 1994 and then, a year later, to BRCA2. Women (and men, too, as it turns out) who carry mutated forms of these genes are far more likely to develop a number of cancers, including breast, ovarian and prostate cancer.

King herself often points to another VIP -- Paul Broca, a French pathologist who first proposed in the 1860s that breast cancer might run in families. Broca's wife suffered from early-onset breast cancer, and when he studied her family tree, he found that the disease could be traced back through four generations. When King went to name the gene she had discovered, she wanted to call it BROCA to honor the Frenchman, but she was only allowed four letters. The final name -- BRCA -- abbreviates "Broca" while standing for "breast cancer" and perhaps even Berkeley, Calif., where King did her doctoral work [source: Check].

Nomenclature aside, the BRCA genes stand as a success story of modern genetics, proving that biomarkers can reliably predict a person's predisposition to develop a disease or condition. A decade or so ago, buoyed by the success of the Human Genome Project, forward thinkers promised a time when biological molecules found in the body would serve as indicators of phenomena such as disease, infection or environmental exposure. These signallers would lead to the eradication of cancer and other pernicious conditions. But a funny thing happened on the way to utopia: Biomarkers proved challenging to identify. And when they were, researchers couldn't develop assays sensitive enough or cost-effective enough to make them valuable diagnostic tools.

So the medical community welcomed the discovery of the BRCA genes, and the development of reliable genetic testing to identify them in individuals, with open arms. All of which has led to the next challenge: making sure the public understands what these genes are.