Objective:To analyze the expression levels of gap junction protein beta 5(GJB5)in pancreatic cancer and its relationship with patient prognosis, and to preliminarily explore its effect on the malignant biological behavior of pancreatic cancer cells.Methods:Using data from the UCSC XENA database, the relative expression level of GJB5 mRNA in human pan-cancer tissues and their correlation with patient prognosis and various clinicopathological characteristics were analyzed. Gene ontology(GO)and Kyoto encyclopedia of gene and genomes(KEGG)analysis in over representation analysis were used to explore the potential biological functions of GJB5. Gene set enrichment analysis(GSEA)was employed to predict the signaling pathways regulated by GJB5-related differentially expressed genes. qRT-PCR was used to detect the expression levels of GJB5 mRNA in human pancreatic ductal epithelial cells(HPNE)and five human pancreatic cancer cell lines(CFPAC-1, PaTu 8988-T, BxPC-3, MIA PaCa-2 and PANC-1), and the optimal pancreatic cancer cell lines were selected for transfection.In vitro experiments, lentiviral transfection was used to establish GJB5 knockdown and overexpression models in human pancreatic cancer PaTu 8988-T and BxPC-3 cells, and to assess the effects of GJB5 on the growth, proliferation, migration, and invasion of pancreatic cancer cells.Results:Bioinformatics analysis showed that the relative expression of GJB5 mRNA was significantly upregulated in pancreatic cancer tissues compared to adjacent normal tissues(P<0.05). High GJB5 mRNA expression levels were significantly correlated with the poor prognosis of pancreatic cancer patients(P<0.05). The expression of GJB5 mRNA was significantly correlated with histological grade of pancreatic cancer patients(P<0.05), and there was no significant correlation with gender, smoking history, alcohol history, T stage and N stage(P>0.05). GO/KEGG analysis indicated that GJB5 plays an important role in various biological processes, including signal release, synaptic signaling regulation, chemical synapse transmission regulation, membrane potential regulation, and hormone transport. GSEA results suggested that GJB5-related differentially expressed genes might be involved in regulating multiple signaling pathways, such as KRAS, apoptosis and protein ubiquitination. Compared with HPNE cells, the relative expression of GJB5 mRNA was significantly increased in the five human pancreatic cancer cell lines(all P<0.05). Knockdown of GJB5 mRNA significantly inhibited the growth, proliferation of PaTu 8988-T and BxPC-3 cells, migration and invasion capabilities of PaTu 8988-T cells; on the contrary, overexpression of GJB5 mRNA promoted the growth, proliferation of PaTu 8988-T and BxPC-3 cells, migration and invasion capabilities of PaTu 8988-T cells.Conclusion:GJB5 is significantly overexpressed in pancreatic cancer tissues and pancreatic cancer cell lines, and GJB5 overexpression is related to the poor prognosis of pancreatic cancer patients, and promotes the malignant growth of pancreatic cancer cells lines PaTu 8988-T and BxPC-3.