Malfunctions in protein tyrosine phosphatase (PTP) activity are linked to various diseases, ranging from cancer to neurological disorders and diabetes, such as CD45, SHP1, TCPTP, PTP1B and LAR linked to cancer, CD45, SHP1 and LAR also linked to neurological diseases, and PTP1B and LAR also linked to diabetes, etc. [9]. The gene discussed is PTPN1; the disease is cancer.