Our rationale for targeting MSLN in MPM is based on our published observations that have shown that: (1) MSLN promotes MPM cell invasion and matrix metalloprotease secretion; (2) MSLN is overexpressed in >90% of patients with epithelioid MPM [23]; and (3) MSLN-targeted CAR T cells delivered regionally to eradicate MSLN-positive pleural tumors align with the regionally aggressive biology of MPM [17]. This evidence concerns the gene MSLN and pleural neoplasm.