STAT3 inactivation is catalysed by PTPRM dephosphorylation and leads to cancer cell death, therefore errors incurred in STAT3 dephosphorylation, such as promoter hypermethylation induced PTPRM transcriptional silencing, may lead to cancer initiation and progression with poor clinical prognosis [84, 95]. The gene discussed is PTPRM; the disease is cancer.