CA125 and human epididymis protein 4 (HE4) are the two U.S. Food and Drug Administration-approved serum biomarkers for ovarian cancer, and HE4 plays an important role in ovarian tumorigenesis.3 The HE4 protein is found in elevated levels in patient serum,4,5 uterine fluid,6 and ascites.7 Investigation illustrates that in addition to CA125 and HE4, the expression levels of OPN,8 mesothelin (MSLN),9,10 Hsp70,11 and AFP12 are related to ovarian tumorigenesis. Here, MSLN is linked to ovarian cancer.