PTPN2 and skin cancer: In epidermal keratinocytes, SHP1 is initially activated in response to ultraviolet B (UVB) exposure and contributes to reduced STAT3 phosphorylation in cooperation with other PTPs, Src homology region 2 domain-containing phosphatase-2 (SHP2) and T-cell PTP (TC-PTP), implying that SHP1 is involved in an initial protective mechanism against UVB-induced skin cancer formation [80].