PTPN1 and colorectal cancer: For example, protein tyrosine phosphatase 1B (PTP1B) is reported to play a tumor-promoting role in prostate and colorectal cancer (Lessard et al., 2012), and high PTPB1 expression is associated with poor prognosis in colorectal cancer patients (Hoekstra et al., 2016; Lessard et al., 2012).