Unlike this suppressor role of HDAC1 on pRb and its interaction with E2F/DP transcription, our data suggests that HDAC1 acts as a potent modulator, suppressing the expression level of CDK inhibitor and augmenting cyclins and CDKs of the cell cycle circuit, especially in the G1/S transition in HCC. This evidence concerns the gene HDAC1 and hepatocellular carcinoma.