Background: Bladder cancer (BLCA) is the most common malignancy of urinary system with a high recurrence rate. We aimed to explore the relationship between cathepsin V (CTSV) expression and prognosis in patients with bladder cancer.
Methods: The RNA-Seq gene expression data and corresponding clinical information with BLCA were downloaded from TCGA database. The gene expression profiles of GSE13507 and GSE133624 were downloaded from GEO database. BLCA patients were divided into high and low expression group according to the cutoff value of CTSV expression. The relationship between clinicopathologic characteristics and CTSV expression was analyzed with the Wilcoxon signed-rank test and logistic regression. Kaplan-Meier analysis and Cox regression were used to analyze the relationship between overall survival and clinicopathologic characteristics. Gene set enrichment analysis (GSEA) was utilized to identify enriched KEGG pathway.
Results: High expression of CTSV was significantly correlated with pathological grade (OR = 1.662 for low vs. high), clinical stage (OR = 1.589 for I-II vs. III-IV), status (OR = 1.435 for normal vs. tumor), T stage (OR = 1.589 for T1-2 vs. T3-4), and M stage (OR = 4.499 for M0 vs M1). The expression of CTSV was significantly increased in BLCA compared with normal tissue (P < 0.001). Kaplan-Meier survival analysis showed that BLCA patients with high expression of CTSV had a poorer prognosis than low expression of CTSV patients (P = 0.0016). Univariate Cox analysis showed that high expression of CTSV was significantly associated with poorer overall survival (HR:1.662, 95%CI:1.209-2.286, P = 0.002). Multivariate Cox regression showed that high expression of CTSV was an independent risk factor for poor prognosis in BLCA patients (HR: 1.495, 95%CI: 1.069-2.089, P = 0.019). We also used the GSE13507 and GSE133624 to verify whether CTSV was differently expressed in bladder cancer tissues and normal tissues. The results showed that CTSV expression was significantly increased in BLCA patients (P < 0.05). Finally, GSEA was used to show 22 enriched signaling pathways in a high phenotype.
Conclusion: High expression of CTSV in bladder cancer is associated with poor prognosis and may serve as a new biomarker. In addition, the chemokine signaling pathway, MAPK signaling pathway, Wnt signaling pathway, JAK-STAT signaling pathway, tight Junction and cell adhesion molecules may be the key pathway regulated by CTSV in BLCA.