ABCB4 and neoplasm: Our findings of a prominent gender disparity in the relative tumor/non-tumor H19 expression in both naïve and hepatectomized Mdr2-KO/FVB mice and of a high H19 expression in the non-tumor liver tissue of Mdr2-KO/FVB females may indicate that H19 has different functions in hepatocarcinogenesis of each gender.