Molecular pathology in early hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors characterized by an obvious multistage process of tumor development. Remarkable progress in diagnostic imaging has led to the discovery of small equivocal lesions, now widely recognized as dysplastic nodule, or early HCC. Early HCC is considered a key step in HCC development and progression. However, the molecular pathology involved in early hepatocarcinogenesis remains unclear due to a lack of corresponding experimental models, difficulty in obtaining fresh samples, and an inconsistency in diagnostic criteria. With gene expression profiling, we have currently identified the overexpression of heat-shock protein 70 and cyclase-associated protein 2 as early HCC signatures. We also recently identified the overexpression of the stemness gene Bmi-1 in early HCC. This overexpression was subsequently found to correlate with ATP-binding cassette transporter B1 expression. These findings give new insight into the mechanism of early hepatocarcinogenesis. Nevertheless, further analysis is still necessary to carefully evaluate the roles of these molecular pathology candidates in early hepatocarcinogenesis.