A study that included 1,893 women with EOC suggested that less than 1% of women with ovarian cancer harbor a germline mutation in the HNPCC genes, and pathogenic mutation carriers had an earlier mean age at diagnosis of ovarian cancer, with a greater likelihood of a non-serous histology, and a greater number of relatives with HNPCC-related cancers [15]. This evidence concerns the gene MLH1 and ovarian cancer.