CA125 in ovarian cancer.

A quarter of a century since its discovery, circulating CA125 antigen is recommended for clinical use in the USA for ovarian cancer screening of high-risk women with ovaries, despite its limited sensitivity and specificity. Recent findings suggest that CA125 might also serve as a predictive marker for pre-invasive ovarian carcinoma. Methods to quantify circulating CA125 evolved toward sensitive and reliable double-determinant ELISA assays. The CA125 gene, MUC16, was cloned 20 years after the protein discovery and revealed a very complex and unusual glycoprotein structure, suggesting an immunological role. Recent evidence points toward CA125 function in the induction of materno-fetal tolerance through the alteration of natural killer phenotype. Two receptors for CA125 have been described: mesothelin and galectin-1. The specific location and functional proprieties of CA125 make it a therapeutic target of choice; clinical trials have demonstrated that anti-CA125 injections are well tolerated and suggest a potential survival benefit.