Objective To investigate the expression pattern and clinical significance of microtubule-associated protein 4(MAP4)in pancreatic adenocarcinoma(PAAD).Methods The immunofluorescence technique was used to detect the expression level of MAP4 in the tissues from 60 PAAD patients visited Liaocheng People's Hospital.The expression levels of MAP4 mRNA and their correlations with patients'prognosis were analyzed using the transcriptome data from 179 PAAD and 332 normal pancreatic tissues in the TCGA and GTEx databases.The correlations of the expression levels of MAP4 with tumor stemness indices,tumor-infiltrating immune cells,and immune checkpoints were analyzed by the bioinformatics method.The small interfering RNA technology was used to silence the expres-sion of MAP4 in PAAD cell lines such as MiaPaCa-2 and PANC-1,and its effects on cell proliferation,migration,and invasion abili-ties were evaluated by the CCK-8 and Transwell assays.Results The results of immunofluorescence showed that the expression levels of MAP4 in PAAD tissues were significantly higher than that in normal pancreatic tissues(P＜0.05).The bioinformatics analysis indi-cated that the expression levels of MAP4 mRNA in PAAD tissues were significantly up-regulated(P＜0.05),and that their high expres-sion was significantly correlated with shorter disease-free and progression-free intervals in patients(P＜0.05).The expression levels of MAP4 were significantly negatively correlated with RNA-related tumor stemness indices(r=-0.55,P＜0.05),but significantly posi-tively correlated with macrophage and dendritic cell infiltration(r＞0.5,P＜0.05).In vitro experimental results confirmed that silencing MAP4 could significantly inhibit the proliferation,migration,and invasion abilities of PAAD cells(P＜0.05).Conclusion MAP4 is highly expressed in PAAD tissues,and its expression levels are closely related to patients'prognosis,tumor stemness,and immune cell infiltration.MAP4 may participate in the progression of PAAD by regulating the biological behavior and immune microenvironment of tumor cells,which provides a new potential target for the diagnosis and treatment of PAAD.

Objective To investigate the expression pattern and clinical significance of microtubule-associated protein 4(MAP4)in pancreatic adenocarcinoma(PAAD).Methods The immunofluorescence technique was used to detect the expression level of MAP4 in the tissues from 60 PAAD patients visited Liaocheng People's Hospital.The expression levels of MAP4 mRNA and their correlations with patients'prognosis were analyzed using the transcriptome data from 179 PAAD and 332 normal pancreatic tissues in the TCGA and GTEx databases.The correlations of the expression levels of MAP4 with tumor stemness indices,tumor-infiltrating immune cells,and immune checkpoints were analyzed by the bioinformatics method.The small interfering RNA technology was used to silence the expres-sion of MAP4 in PAAD cell lines such as MiaPaCa-2 and PANC-1,and its effects on cell proliferation,migration,and invasion abili-ties were evaluated by the CCK-8 and Transwell assays.Results The results of immunofluorescence showed that the expression levels of MAP4 in PAAD tissues were significantly higher than that in normal pancreatic tissues(P＜0.05).The bioinformatics analysis indi-cated that the expression levels of MAP4 mRNA in PAAD tissues were significantly up-regulated(P＜0.05),and that their high expres-sion was significantly correlated with shorter disease-free and progression-free intervals in patients(P＜0.05).The expression levels of MAP4 were significantly negatively correlated with RNA-related tumor stemness indices(r=-0.55,P＜0.05),but significantly posi-tively correlated with macrophage and dendritic cell infiltration(r＞0.5,P＜0.05).In vitro experimental results confirmed that silencing MAP4 could significantly inhibit the proliferation,migration,and invasion abilities of PAAD cells(P＜0.05).Conclusion MAP4 is highly expressed in PAAD tissues,and its expression levels are closely related to patients'prognosis,tumor stemness,and immune cell infiltration.MAP4 may participate in the progression of PAAD by regulating the biological behavior and immune microenvironment of tumor cells,which provides a new potential target for the diagnosis and treatment of PAAD.