BRCA1 and serous adenocarcinoma: In ovarian cancer (Table 4), hypermethylation of BRCA1 was detected at a significantly higher frequency in serous carcinomas than in tumors of the other histological types (35.3% versus 6.2%, P = 0.015], whereas, PTEN were more frequently detected in mucinous carcinoma than in tumors of the other histological types (30% versus 2.6%, P = 0.023).