IRS1 and hepatocellular carcinoma: As shown in Fig. 4c, the verification results of JUN and IRS1 were consistent with the results of gene expression profiling, and they were significantly down-regulated by PYCR1 interference in both mRNA and protein levels (P < 0.001), implying that PYCR1 might influence HCC cells proliferation and apoptosis by regulating JNK/IRS1 pathway.