Several generations of immunotoxins, such as SS1P and LMB100, were engineered by conjugation of anti-human MSLN SS1 Ab [72,79,126] to PE38 (truncated Pseudomonas exotoxin) [127], and successfully tested in clinical trials in patients with mesothelioma, ovarian cancer and pancreatic cancer [125,128,129,130]. Here, MSLN is linked to ovarian carcinoma.