BRCA2 and serous adenocarcinoma: Regarding the difference between BRCA1 and BRCA2 in the frequency of histological types in each country, the frequency of serous carcinoma in cases with BRCA1 or BRCA2 mutation was about 80%, and there was almost no difference between BRCA1 and BRCA2. Among ovarian cancer patients in China and South Korea, five cases of mucinous carcinoma with BRCA1/2 mutation were found, of which three cases had a BRCA1 mutation and two cases had a BRCA2 mutation.