FOXO1 and hepatocellular carcinoma: Conversely, siRNA-induced knockdown of SKP2 led to growth restraint of HuH7 human HCC cells (expressing high SKP2 levels), which was paralleled by increase in the levels of P21WAF1, P27KIP1, P57KIP2, P130, FOXO1, and RASSF1A proteins [38].