High expression of JAM2 indicates better prognosis and immunotherapy response in breast cancer

In our study, multiple databases were used to explore the potential role and underlying mechanism of junctional adhesion molecule B (JAM2) in breast cancer (BRCA). The data of JAM2 was downloaded from The Cancer Cell Line Encyclopedia (CCLE), the Genotype-Tissue Expression (GTEx), The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) databases. Receiver operating characteristic (ROC) curve analysis was performed to analyze the area under the curve (AUC) of JAM2 expression correlated with normal breast tissue and breast cancer tissue. Gene set enrichment analysis (GSEA) was used to identify the potential biological mechanisms of the JAM2. The expression of JAM2 mRNA were downregulated In most tumors, including BRCA, which may be due to the hypermethylated status. The AUCs, which were 0.929 and 0.887 by the logistic regression and random forest algorithms, indicated that JAM2 mRNA expression have good diagnostic value in BRCA. Univariate and multivariate analyses indicated JAM2 as an independent prognostic factor for the overall survival of BRCA patients in both the TCGA cohort (HR = 0.62, P = 0.034) and METABRIC cohort (HR = 0.77, P = 0.001). GSEA showed that multiple tumor pathways were suppressed in the JAM2 high expression group. The expression of JAM2 was most positively related to the epithelial-mesenchymal transition (EMT) score (r = 0.38; P <0.01) by the reverse-phase protein array (RPPA) analysis. Patients with high JAM2 expression may be more sensitive to immunotherapy. 18 chemotherapy drugs that patients in the JAM2 low expression group were more sensitive to were identified. Our results demonstrated the diagnostic and prognostic value of JAM2. Analysis of the molecular mechanisms indicates the potential role of JAM2 as a tumor suppressor, and high JAM2 expression may predict a better immunotherapy response in BRCA.