The downregulation or loss of SHP1 protein expression is a characteristic of human lymphoma and leukemia, and in fact, methylation of the PTPN6 promoter, resulting in suppressed SHP1 expression, was found in anaplastic large cell lymphoma (ALCL), multiple myeloma, T-cell lymphoma, and B-cell lymphoma [68,69,70,71,72,73,74]. Here, PTPN6 is linked to leukemia.