Conversely, STAT3 mutant Tyr640Phe (DB’1), which is a commonly identified mutation in solid and liquid tumors, leads to constitutive activation across several cell lines (hepatic epithelial cells, lung carcinomas, fibroblasts, etc.)through enhanced stability of STAT3 dimerization, nuclear accumulation and increased transcriptional activity following IFNγ stimulation [44,47,48,59,60,61,62,65,66,67,68,69]. The gene discussed is STAT3; the disease is lung carcinoma.