As immortalization is also a first step of carcinogenesis and a variety of human cancer cells including breast, colon, kidney, lung, and ovarian cancer cells share not only genomic instability, loss of senescence genes, mutation in p53 genes, and high proliferation rate but also the constitutively high expression of GSTP1 [25–27], the role of GSTP1 in HaCaT cells might be distinct from that of the normal cells. The gene discussed is TP53; the disease is cancer.