BRCA1 mutations account for only 5% of breast and ovarian
cancers, but loss-of-function mutations in the BRCA1 gene confer
up to an 82% risk of breast cancer and up to a 54% risk of
ovarian cancer. Because BRCA1 is involved in DNA repair, loss of
a functioning BRCA1 gene may make a cell more vulnerable to
chemotherapy agents that damage DNA, such as platinum-based
compounds. In addition, BRCA1 has also been shown to be involved
in the regulation of cell division, and loss of the gene has
been proposed to protect a cell against spindle poisons, a group
of chemotherapy agents, such as taxanes and vinca alkaloids,
that disrupt cell division. To determine whether the level of
BRCA1 function in a patient could be used to predict response to
chemotherapy for breast and ovarian cancers, D. Paul Harkin,
B.Sc., Ph.D., and Richard D. Kennedy, M.D., Ph.D., of The
Queen's University of Belfast in Northern Ireland, and
colleagues reviewed published preclinical and clinical evidence.
Preclinical studies included research i