Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, is mainly due to genetic changes in hepatocytes. However, molecular expression in hepatocytes during hepatocarcinogenesis has not been characterized. In this study, using an inducible kras transgenic zebrafish models for HCC, transcriptomic profiles of oncogenic hepatocytes from larvae, male and female adult fish following a brief induction of oncogenic kras were investigated. We found that oncogenic hepatocytes from all the three sources possess most of the cancer hallmarks at molecular level, including Sustaining proliferative signaling, Evading growth suppressors, Resisting cell death, Avoiding immune destruction, Inflammation, Reprogramming of energy metabolism, Angiogenesis, and Activating invasion and metastasis, suggesting the malignant transformation at molecular level could occur at the early stage of hepatocarcinogensis and can be captured in hepatocytes. However, each group of oncogenic hepatocytes also had their own characteristics. Larval oncogenic hepatocytes have cancer stem cell features. Female oncogenic hepatocytes showed resemblance to a mild human HCC subtype while male oncogenic hepatocytes resembled a severe HCC subtype, consistent with the observed sex disparity of HCC in both zebrafish and human. Finally, the two adult groups were more similar to each other than to the larval group, indicating an overwhelming effect of development over the gender. (C) 2019 Elsevier Inc. All rights reserved.