PTPN21 and colorectal carcinoma: As for CRC patients, the expression of PTPN1, PTPN3, PTPN7, PTPN11, PTPN12, PTPN13 and PTPN14 was upregulated, while PTPN2, PTPN18, PTPN20, PTPN21 and PTPN22 were expressed in a lower level in tissues.