VIPR1 and hepatocellular carcinoma: To better understand the role of VIP/VIPR1 signaling in regulating HCC biological functions, we also used Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment to analyze transcriptome data and found that several tumorigenic pathways (such as PI3K-AKT, TNFα and NF-κB signaling pathways) were altered in the VIP/VIPR1 group versus the control group (Fig. 4C).