Therefore, it remains elusive whether the expression of CK-19, as well as of other HPC markers, represents i) retention of a progenitor cell phenotype all throughout the carcinogenic process or ii) the result of de-differentiation of preneoplastic or malignant hepatocytes to a progenitor cell/biliary phenotype during progression towards HCC. The gene discussed is KRT19; the disease is hepatocellular carcinoma.