MSLN and mesothelioma: Based on potent anti-tumor effects observed in preclinical studies using mRNA electroporation [37], an initial study focusing on toxicity assessment was conducted (NCT01355965) at the University of Pennsylvania using T cells that only transiently expressed the second-generation anti-mesothelin CAR that contained the CD3ζ and 41BB signaling domains (7 mesothelioma patients and 7 pancreatic cancer patients) [29,38].