MSLN and cancer: Mesothelin is a 40-kDa cell surface glycoprotein, which is highly expressed in several human cancers (Chang and Pastan, 1996), including lung cancer (∼50% of cases) (Ordóñez, 2003), ovarian cancer (∼70% of cases) (Hassan et al., 2005) and pancreatic/biliary adenocarcinomas (∼100% of cases) (Argani et al., 2001).