Malignant transformation of endometriosis: application of laser microdissection for analysis of genetic alterations according to pathological changes.

Endometriosis is considered to be a possible precancerous disease. Pathologically, we observed malignant transformation of endometriosis to clear cell carcinoma or endometriotic carcinoma of the ovary, via the step of atypical endometriosis. Pathological changes reflected genetic alterations. In cases of clear cell carcinoma, we assessed K- ras mutations in regions of normal endometriosis, atypical endometriosis, and clear cell carcinoma, and obtained tissue samples by laser microdissection. We found that K- ras mutations were associated with malignant transformation of clear cell carcinoma. The present results indicate that laser microdissection can be used to combine assessment of genetic and pathological changes.