“…It is well established that bile duct differentiation by hepatoblasts takes place in periportal areas in the fetal stages of humans and rodents (Bloom, 1926;Enzan et al, 1974;Haruna et al, 1996;Horstmann, 1939;Shiojiri, 1981Shiojiri, , 1994Shiojiri et al, 1991;Terada et al, 1998;Terada and Nakanuma, 1994;Van Eyken et al, 1988a, 1988b. Immunohistochemical studies have shown that hepatoblasts are a homogeneous population in terms of expression of alpha-fetoprotein, albumin, and cytokeratins before the appearance of periportal bile duct progenitors (Shiojiri, 1981;Shiojiri et al, 1991;Van Eyken et al, 1988a, 1988b.…”