MUC16 and endometriosis: Although transvaginal ultrasound can detect structural abnormalities, its sensitivity for distinguishing benign from malignant conditions is only 74-83%.3 The most widely used biomarker, cancer antigen 125 (CA125), suffers from inadequate sensitivity and specificity.4 Its sensitivity is particularly low for early-stage lesions (around 50%) and certain subtypes such as mucinous and clear cell carcinomas.5 It is also elevated in benign conditions like endometriosis and pelvic inflammatory disease, leading to a high false-positive rate.6