| Objective: Polypeptide N-acetylgalactosaminyltransferase 15(GALNT15)is a member of the polypeptide N-acetylgalactosaminyltransferases(pp-Gal NAc-Ts)family.It is shown in some studies that pp-Gal NAc-Ts is closely related to the occurrence and development of many kinds of cancers,but the function of GALNT15 in the prognosis of gastric cancer has not been reported so far.This study aims to explore the significance of GALNT15 as a prognostic biomarker for gastric cancer and its promotion value in pan-cancer.Methods: Data on tumor and normal tissues were extracted from The Cancer Genome Atlas(TCGA).We conducted differential analyses of GALNT15 expression in gastric cancer and normal tissues.To evaluate the accuracy of GALNT15 in diagnosing gastric cancer,we plotted the receiver operator characteristic curve(ROC).Subsequently,we evaluated the association of the expression levels of GALNT15 with the clinical characteristics of gastric cancer by means of a correlation analysis.We divided gastric cancer patients into low-expression and high-expression groups based on the expression level of GALNT15 and presented the differences in overall survival(OS)and disease-specific survival(DSS)through log-rank test.And then,biological processes associated with GALNT15 in gastric cancer were identified through gene-set enrichment analysis(GSEA),and the correlation of the immune microenvironment with GALNT15 was preliminarily assessed in gastric cancer by the CIBERSORT algorithm.On this basis,we further explored the association of GALNT15 with immune checkpoint genes and the efficacy of immune checkpoint blockade.Then,based on univariate and multivariate Cox regression analyses,a nomogram was made to predict the survival rates of patients with gastric cancer.Finally,in order to explore the potential prognostic value of GALNT15 in pan-cancer,we conducted similar analyses on the association of GALNT15 with other cancers.Results: Compared with normal tissues,GALNT15 was significantly less expressed in gastric cancer tissues.The accuracy of GALNT15 in the diagnosis of gastric cancer was confirmed by the receiver operator characteristic curve(ROC).We also found that the expression of GALNT15 was significantly correlated with the pathological grade,pathologic T stage,race,histological types,overall survival,and disease-specific survival of patients with gastric cancer.And Overall survival and disease-specific survival in the high-expression group were significantly shorter than those in the low-expression group.Next,through gene set enrichment analysis(GSEA),we found that the expression of GALNT15 in gastric cancer was correlated with multiple cancers and immune pathways.Meanwhile,the expression of GALNT15 has also been confirmed to be closely related to the infiltration level of immune cells,especially tumor-associated macrophages.In addition,we found that GALNT15 co-expressed with some immune checkpoint genes and was significantly associated with response to immune checkpoint blockade.To accurately predict the survival status of patients with gastric cancer,we combined age,pathological N stage,initial treatment results,and GALNT15 expression level to construct a nomogram.Finally,further pan-cancer analyses showed that GALNT15 was abnormally low expressed in multiple tumor tissues,and GALNT15 was closely associated with prognosis in multiple cancers.Correlation analysis with immune factors of 32 other tumors showed that GALNT15 was closely related to antitumor immunity.Conclusion: GALNT15 is a novel molecular marker that can be used to predict the prognosis of patients with gastric cancer.It is closely associated to the dynamic changes of immune infiltrating components in the immune microenvironment of gastric cancer.And this conclusion also has the value of generalization in pan-cancer. |
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