DNA mismatch repair (MMR) deficiency is associated with increased risk of developing several types of cancer and is the most common cause of hereditary ovarian cancer after BRCA1 and BRCA2 mutations.
BRCA1 and BRCA2 germline mutations are the most common genetic defects underlying hereditary ovarian cancer, which is why ovarian cancer risk assessment in developed countries, aside from pedigree analysis, relies on genetic testing of BRCA1 and BRCA2.
We evaluated 241 consecutive women with a BRCA1 or BRCA2 mutation who were enrolled in the surveillance program for hereditary ovarian cancer from September 1995 until May 2006 at the University Medical Center Groningen (UMCG), The Netherlands.
The purpose of this study was to compare the clinical characteristics of BRCA1- and BRCA2-associated hereditary ovarian cancer, hereditary ovarian cancer with no identified BRCA1/2 mutation, and ovarian cancer in population-based controls.
Genetic linkage analyses reveal that the majority of breast and ovarian cancer families are linked to the BRCA1 gene, while some cases of hereditary ovarian cancer are also apparent in breast cancer families linked to the BRCA2 gene.
Unlike BRCA1, however, which confers a high risk to both breast and ovarian cancer, the incidence of ovarian cancer appears to be much lower In BRCA2-linked families, causing uncertainty as to the relevance of BRCA2 to hereditary ovarian cancer.