MSLN and malignant mesothelioma: To date, several immunotherapeutic modalities, most notably, anti-mesothelin immunotoxins, have been successfully implemented for the treatment of mesothelin-expressing solid tumors, including ovarian carcinomas [5], pancreatic adenocarcinoma [6], and malignant mesothelioma [7], while mesothelin-targeting chimeric antigen receptor (CAR) T cells have shown significant anti-tumor effects [8,9,10].