Nakayama K, Nakamura K, Ishibashi T, Sanuki K, Ishikawa M and Kyo S
Two models of carcinogenesis have recently been proposed for ovarian cancer based on the differences in the mechanism of carcinogenesis. Low-grade serous carcinoma and mucinous carcinoma are classified as type I, and high-grade serous carcinoma and high-grade endometrioid carcinoma are classified as type II ovarian cancers. Low-and high-grade serous carcinomas were reported to have independent pathologies based on their morphological characteristics, molecular mechanism of histogenesis, and clinical features. Serial activation of the components of the mitogen activated protein kinase (MAPK) signaling pathway was observed in low-grade serous carcinomas resistant to existing anticancer drugs, and the efficacy of MEK inhibitors targeting these signals has been demonstrated. The morphology- and molecular biology-based elucidation of the pathology of ovarian cancers might lead to the implementation of personalized treatment through molecular-targeted therapy.