MKI67 and cancer: Since its discovery as an antigen for a monoclonal antibody against a Hodgkin lymphoma cell line more than 30 years ago (Gerdes et al., 1983; Gerdes et al., 1984), Ki-67 serves as the most useful biomarker of cancer in clinical practice (Brown and Gatter, 2002; Yerushalmi et al., 2010; Martin et al., 2004).