The MCM2-positive cell ratio was significantly higher in clear cell carcinoma with cytoplasmic/nuclear staining (CCC-C) than in serous carcinoma, endometrioid carcinoma, and clear cell carcinoma with nuclear staining (CCC-N) (P < 0.01, P < 0.01, P < 0.05, respectively). Here, MCM2 is linked to clear cell adenocarcinoma.