The Origin of Ovarian Cancer — Is It Getting Clearer?

The association of endometriosis and ovarian cancer was first reported by Sampson in 1925.1 Transitional areas of endometriosis, ranging from benign to atypical, adjacent to ovarian cancer have been well documented.2 The risk of ovarian cancer among women with endometriosis is higher, by 30 to 40%, than among women without endometriosis. The vast majority of ovarian cancers associated with endometriosis are clear-cell or endometrioid carcinomas. The early development of ovarian cancer remains poorly defined. Historically, most attention has been focused on serous adenocarcinoma, the most common and lethal histologic type. These tumors have been thought to arise from the surface . . .