HIPK2 and hepatocellular carcinoma: In human prostate cancer cells and hepatocellular carcinoma cells, HIF-1α transcriptionally induces its targets to promote the proteasomal degradation of HIPK2, and thus, HIF-1α reduces p53 activities and p53-dependent apoptosis through downregulating HIPK2 (Nardinocchi et al., 2011; Chen et al., 2020).