TP53 and hepatocellular carcinoma: We found that although TP53 protein levels in cancer tissues were similar in both HCC groups, p21waf1/cip1 expression was significantly higher in the pTAC group than in the non-pTAC group, indicating that in spite of defective TP53 protein in tumor cells, oxidative stress was upregulated in response to chemotherapy via an alternative pathway.