MSLN and malignant mesothelioma: Mesothelin (MSLN), among others, has emerged as a promising target for CAR T cell therapy due to its expression profile.8 MSLN, a GPI-anchored glycoprotein, is overexpressed in several solid tumors including pancreatic cancer, malignant mesothelioma, and ovarian cancer, while expression in healthy tissues is restricted to mesothelial cells.