BRCA2 germline mutations in Swedish breast cancer families.

Mutations in the breast cancer susceptibility gene (BRCA2) are believed to be responsible for a significant fraction of hereditary breast cancer. To determine the BRCA2 mutation spectrum in a subset of Swedish breast cancer families, 162 families were screened for germline mutations in this gene. A combination of RT-PCR, PTT and direct DNA sequencing was used. Two mutations and one previously reported polymorphic variant resulting in a truncated protein were identified. Our data suggest that only a small proportion of Swedish breast cancer families is attributable to BRCA2 germline mutations. This result, in combination with the low frequency of BRCA1 germline mutations identified in our previous study, suggests additional high penetrant as well as low penetrant breast cancer susceptibility genes are involved in familial breast cancer.