PTPN6 and neoplasm: For example, tumor suppressor genes, such as p15 (CDKN2B) [3], p16 (CDKN2A) [4], p57 (CDKN1C) [5], p73 (TP73) [6], SHP-1[7] and DAPK[8], are frequently hypermethylated and related to tumor progression in lymphoid malignancies.