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. Here, MSLN is linked to ovarian cancer.