AbstractBackgroundThe Wnt/β‐catenin signalling pathway regulates genes involved in cell proliferation, survival, migration and invasion through regulation by T‐cell factor (TCF)‐4 transcription factor proteins. However, the role ofTCF‐4 isoforms generated by alternative splicing events in hepatocellular carcinoma (HCC) is unknown.AimHere, we investigatedTCF‐4 isoforms (TCF‐4J and K)‐responsive target genes that are important in hepatic oncogenesis and tumour development.MethodsGene expression microarray was performed onHCCcells overexpressingTCF‐4J and K isoforms. Expression level of selected target genes was evaluated and correlations were made between their expression level and that ofTCF‐4 isoform in 47 pairs of humanHCCtumours.ResultsComparison by gene expression microarray revealed that 447 genes were upregulated and 343 downregulated more than 2.0‐fold inTCF‐4J compared withTCF‐4K expressing cells. We validated expression of 18 selected target genes involved in Wnt/β‐catenin, insulin/IGF‐1/IRS1 and Notch signalling pathways in 47 pairs of humanHCCs and adjacent uninvolved liver tissues. It was observed that 13 genes (CLDN2,STK17B,SPP1,AXIN2,WISP2,MMP7,IRS1,ANXA1,CAMK2N1,ASPH,GPR56,CD24 andJAG1) activated byTCF‐4J isoform inHCCcells, were also upregulated inHCCtumours compared with adjacent peritumour tissue; more importantly, 10 genes exhibited a significant correlation with theTCF‐4J expression level in tumour.ConclusionTCF‐4 isoforms (TCF‐4J and K) activated different downstream target genes inHCC. The biological consequence ofTCF‐4J isoform expression was upregulation of genes associated with tripartite Wnt/β‐catenin, insulin/IGF‐1/IRS1 and Notch signal transduction pathway activation, which contribute to the pathogenesis ofHCC.