**Endometriosis-Associated Ovarian Cancer: The Role of Oxidative Stress**

Yoriko Yamashita and Shinya Toyokuni *Nagoya University Graduate School of Medicine, Japan* 

## **1. Introduction**

Recent studies indicated that oxidative stress has a causal role in the carcinogenesis of mainly two histological subtypes of ovarian cancer, namely, clear cell carcinoma and endometrioid adenocarcinoma. Because of recurrent hemorrhage in endometrial cysts, excess of reactive oxygen species are produced due to iron deposition, which results in direct genomic mutation of the epithelial cells and exaggeration of oxidative stress by stromal cells such as macrophages. In endometriosis-associated ovarian cancer, genomic mutations in specific genes such as ARID1A, p53, K-ras, PTEN, PI3CA and Met have been reported. Mechanism of carcinogenesis, especially focusing on the precise role of oxidative stress, remains to be clarified. Development of novel drugs and methods for therapy or prevention of endometriosis-associated ovarian cancer is necessary.
