Chen et al. demonstrated that 4-HNE was increasingly expressed in nicotine and cotinine-aggravated alcoholic liver disease mice models, stimulating the effect of Cdkn1a-encoded P21, which ultimately impaired the regeneration markers of hepatocytes, including the proliferating cell nuclear antigen (PCNA) and Ki67 [108]. This evidence concerns the gene CDKN1A and alcoholic liver diseases.