Endometriosis-associated cancer.

Endometriosis will affect about 10% of the female population and not only can it significantly impact adversely on quality of life and result in infertility, but data are accumulating that malignant transformation is an important consideration. Endometriosis can be histologically typical or atypical, ovarian, superficial peritoneal or deep infiltrating. The precursor for malignant transformation appears to be the ovarian atypical endometriosis component. Ovarian cancer is the most important associated cancer, primarily endometrioid and clear cell cancer. These are the only subtypes wherein a direct clonal relationship between endometriosis, as a direct precursor, and cancer has been made. There is no substantive evidence to support an altered association of borderline cancers of the ovary, serous ovarian cancers and breast, endometrial or cervical cancers. This review provides an overview of the prevailing data pertaining to the molecular and genetic aberrations that accompany the transformation of atypical endometriosis to malignancy and the accumulated epidemiologic evidence which supports the association.