Furthermore, in 63–78% of early-stage ovarian cancer patients and 50–58% of patients with less frequently diagnosed histology subtypes (including clear cell carcinomas, mucinous carcinomas, and sex-cord stromal tumors), those with a low CA125 level could be identified by OVCA1 [60,61,62]. This evidence concerns the gene MUC16 and clear cell adenocarcinoma.