SIRT4 and hepatocellular carcinoma: In contrast, increased mRNA and protein expression of SIRT3 and SIRT4 has been found to be beneficial for patient outcomes in hepatocellular carcinoma (HCC), and higher levels of SIRT3 mRNA and protein expression in HCC cell lines increased sensitivity to cisplatin, doxorubicin, epirubicin, sorafenib, and regorafenib [32].