CK18 is primarily expressed in single-layered or “simple” epithelial tissues of, for example, the liver, kidney, breast, prostate, gastrointestinal tract as well as in cancers arising from CK18 positive epithelial cells (Oshima et al. 1996; Cajaiba et al. 2006; Skinnider et al. 2005; Faridi et al. 2018). The gene discussed is KRT18; the disease is cancer.