To assess whether targeting of PTPN2 might enhance the cytotoxic potential of human CAR T cells, we took advantage of human CAR T cells targeting the Lewis Y (LY) antigen (Westwood et al, 2008; Peinert et al, 2010) that is overexpressed in many human cancers, including 80% of lung adenocarcinomas, 25% of ovarian carcinomas and 25% of colorectal adenocarcinomas (Fig 8A). Here, PTPN2 is linked to ovarian carcinoma.