MSLN and cancer: Studies of human ovarian cancer have revealed that the cancer antigen CA125 can serve as a ligand of MSLN [76,77], and co-expression of MUC16 and MSLN is known to be associated with the invasion process of cancers [78,79,80,81], with MUC16 promoting the potential role of MSLN in tumor adhesion, and metastasis [76,82].