This year's Genetics Guide focuses on BRCA1 and BRCA2--tumor-suppressing genes that, in normal cells, help stabilize the cell's DNA and prevent uncontrollable cell growth. Harmful mutations in BRCA genes can lead to increased risk of breast or ovarian cancer in women: About 60 percent of women who inherit either mutation will develop one of these cancers during their lifetimes, compared to 12 percent in the general population. Men with a BRCA gene mutation have a higher risk of developing breast, prostate and skin cancers. While hundreds of cancer-associated BRCA1 and BRCA2 mutations have been documented, three specific mutations, two in the BRCA1 gene and one in the BRCA2 gene, are more prevalent in people of Ashkenazi Jewish ancestry: One out of 40 will inherit a BRCA1 or 2 mutation. Moment explores the fascinating story behind BRC2-Vs discovery and provides a glimpse into BRCA research, warning signs and treatment.
GENETICS PIONEER MARY-CLAIRE KING
In 1990, Mary-Claire King discovered the first evidence for the existence of a gene that was associated with breast cancer. The gene she named BRCA changed the way people thought not only about breast cancer but about the genetics of other common cancers and diseases as well. King--a professor of medicine and genetics at the University of Washington--tells Moment about how she became interested in studying inherited cancers, what the letters B-R-C-A signify, and why testing for BRCA mutations should be universal.
How did you become involved in the field of breast cancer genetics?
I got involved by doing what would now be called a post-doc. I had finished my PhD in genetics at Berkeley in 1972, showing that humans and chimpanzees are, genetically, 99 percent identical. I then went with my husband to Chile to teach but was forced to return after the 1973 coup. When I returned to the Bay Area I needed a job and wanted to do something meaningful. This was at the time Nixon had declared "war on cancer," and there was money set aside to study cancer in-depth. I was delighted to be offered a position in San Francisco with carte blanche to do work on breast cancer. I thought my background in mathematics could transfer nicely to see if and how cancer evolves as it passes from one generation to another in a single family. To prove this, I had to show that this genetic component could be physically mapped on a specific chromosome. It took 17 years, but we identified that the...