PTPN2, also known as T cell protein tyrosine phosphatase (TCPTP), dephosphorylates the insulin receptor, EGFR, Src family kinases, JAK, and STAT, and has a key role in IBD.189,190 PTPN2 regulates normal interactions between innate and adaptive immune cells and intestinal epithelial cells and has a protective function for the intestinal barrier.191,192 PTPN2 knockout or loss-of-function PTPN2 SNP rs189321737 mutation led to macrophage polarization to the proinflammatory M1 phenotype through the regulation of IL-6 and STAT1. This evidence concerns the gene PTPN2 and inflammatory bowel disease.