Mesothelin is frequently expressed on RM and MM, but despite earlier claims that its expression is limited to cells of mesothelial lineage (Urwin, 2000; Ordonez, 2003b), has been shown to be expressed in several tumor types, including non-mucinous ovarian, lung and pancreatic AC (Miettinen, 2003; Ordonez, 2003b). Here, MSLN is linked to neoplasm.