HNF4A and fatty liver disease: Although the presence of hepatic steatosis caused major histological aberrations, there appeared to be only a modest increase in the frequency of EGFP or CCN2 signal in either HNF4α-positive fat-laden hepatocytes (Figure 4A) or periportal CK19-positive biliary epithelial cells (Figure 4B), although some CK19-positive cells were localized in the sinusoidal regions and were negative for EGFP.