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Genetic Testing for BRCA1 and BRCA2

October 13, 2011  |  Jane Belland Karwoski PhD

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Most breast cancer is not hereditary.  Available estimates say that genetic susceptibility (among Caucasian women) is involved in 5 to 10% of breast malignancies and 10 to 15% of ovarian cancers (BRCA mutations can cause either). We all possess wonderful genes called tumor suppressors. Two of the genes known to suppress breast and ovarian cancer tumors are called BRCA1 and BRCA2.  BRCA (pronounced brack’ uh) stands for BReast CAncer.  Normally, we have two healthy copies of each tumor suppressor gene.  When a mutation, or change, occurs causing one gene to work incorrectly, the cell can still continue to suppress abnormal growth UNTIL something breaks the second gene as well. When both genes of a pair are damaged, the gene can no longer work its tumor suppressing magic and cancer can result. So when one inherits a BRCA gene with a harmful mutation, it means there is just one gene, instead of a pair, standing guard, resisting tumor-generating forces.  One’s risk of breast cancer is then higher than that of the general population.  It could be as much as five times higher, 60% instead of 12%, although this might be an overestimate. (Source: Factsheet/Risk/BRCA#a2).

It is important to appreciate that not all children of an adult with a BRCA1 or BRCA2 mutation will inherit the damaged gene instead of the healthy one. Genetic counselors can help various family members estimate the risk they face.  Naturally, those who have experienced the disease, or survivors who knew relatives who were killed by it, feel great concern for relatives that may face increased risk.  However, knowledge of risk is something not everyone desires. Perception of the burden of having breast or ovarian cancer varies also. But what about minor children?  For many years, most genetics professionals have counseled against genetic testing of children to determine either carrier status or genetic susceptibility.  Personally, I am convinced that it is not the test or test results themselves that can be harmful to children. Rather, it is the meaning given those results by the adults with influence over the children.  Even mature teenagers are vulnerable to being overwhelmed by their parents’ interpretation of test results.  One must have the fortitude to override worry and concern in order to respect family member’s autonomy and right to make their own decisions in the wake of genetic knowledge, regardless of their age or attitude.

Jane Belland Karwoski, PhD, LMSW, is a research psychologist in the field of psychosocial genetics. Her blog: http://www.mybluegenome.com explores the psychosocial components of genetic testing and disease.