MUC16 and endometriosis: By comparing the classifier with carbohydrate antigen 125 (CA125), a commonly used biomarker for ovarian cancer, we found that the classifier displayed improved diagnostic capabilities for early-stage disease and borderline ovarian tumors in three external validation cohorts, and for non-epithelial ovarian malignancies and discriminating ovarian cancer from endometriosis in two Chinese external validation cohorts.