PTPN6 and Familial prostate cancer: <b>Background/Objectives:</b> Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1), also known as protein tyrosine phosphatase non-receptor type 6, functions as a tumor suppressor in breast, hepatocellular, and prostate cancers and an oncogene in glioblastoma and cervical cancer.