BRCA1 and BRCA2: No Longer the Only Troublesome Genes Out There
By now, most of us are probably pretty familiar with the BRCA1 and BRCA2 genes. Identified in 1990, they were the first genes positively linked with an increased risk for breast cancer. Since then, it's been determined that women whose heritage is Ashkenazi Jewish are about 10 times more likely to carry one or the other of these genes than the regular population.
The bad news is, abnormalities in these genes put the women who carry them at 50 percent to 85 percent increased risk of getting breast cancer. The "good" news is, only 5 percent to 10 percent of breast cancer cases are a result of these genes. Many women, particularly those with a strong family history of breast cancer, have genetic testing done; thankfully, most test negative for these genes.
Now, however, scientists have identified four more genes that increase breast cancer risk. The bad news is, one or more of these genes is found in a significantly higher percentage of the population than the BRCA genes. The good news is? Well, let's see, what IS the good news?
In a study funded by grants from the National Cancer Institute (NCI) and the American Cancer Society, researchers showed that mutations in four separate genes are more common in women with breast cancer than in a control group of cancer-free women. The study focused on one particular gene, FGFR2, which, if you're of European ancestry and have inherited a particular variant from your parents, may increase your risk of breast cancer. Results of this study, undertaken by the Harvard School of Public Health, Boston's Brigham and Women's Hospital, and the NCI, were published May 27.
So, what does this mean?
"This is a truly landmark breakthrough for breast cancer research, because these genes are the first confirmed common genetic risk factors for breast cancer," notes Singapore scientist Jianjun Liu, a participant in the study. Added David Hunter, M.D., of Harvard, lead author of the study's paper: "This finding opens up new avenues of research into the causes and prevention of breast cancer by identifying a new biological pathway relevant to risk of the disease."
In other words, identification of this gene is another big step in the long, laborious search for a breast cancer cure. You have to know what's causing a problem before you can fix it; and FGFR2 appears to be a likely culprit.
Though just one of many, notes Teri Manolio, M.D., director of population genetics at the National Human Genome Research Institute: "There is no single breast cancer gene just as there is no single diabetes gene or prostate cancer gene," he says. "What we have is many genes of small effect that, working together and with specific-and as yet largely unknown-environmental exposures, cause a woman to develop breast cancer."
In other words, FGFR2 is just part of a much larger crowd. And, thankfully, at this point, it doesn't appear to carry nearly the risk that the BRCA genes do.
Still, should a genetic test for FGFR2 be developed and offered to women? And if so, at what cost? Current genetic testing costs upwards of $3,000 or more, and many insurance companies won't cover it. Listen to Dr. Hunter: don't call your local cancer center to ask for genetic testing just yet. "It is premature to recommend screening women for these gene variants, at least until the scientific community has found all the variants that are associated with increased risk," he says.
Bottom line: be patient. An expansion of genetic testing may be down the road, but for now, only those with a strong family history of breast cancer, or other indicating factors, need to be tested.