CDKN1C and hepatocellular carcinoma: Xu Q. et al. (2018) and Yang J. B. et al. (2016) showed that α-pinene induced G2/M phase cell cycle arrest and inhibited miR-221 expression with downstream up-regulation of CDKN1B/P27 and down-regulation of CDKN1C/P57 in HCC cells. The mechanism through which miR-221 regulates CDKN1C/P57 and CDKN1B/P27 was not elucidated in this study, but another study revealed that CDKN1B/P27 is a direct target of miR-221 (Diaz-Moralli et al., 2013).