To investigate the expression of TIA1 gene in bladder cancer (BLCA) and its effect on the occurrence, development and prognosis of BLCA.

Based on TCGA database, the relationship between TIA1 gene expression and bladder cancer survival prognosis and diagnostic value were analyzed using Kaplan-Meier curve and ROC curve.The association between TIA1 expression and clinical features were analyzed by rank sum test. Univariate and multivariate Cox regression analysis of TIA1 and clinical features predicted the possibility of prognosis in BLCA patients, and a nomogram was constructed to predict the progression-free survival of BLCA patients. Gene set enrichment analysis (GSEA) was used to explore the potential mechanism of action of TIA1 in bladder cancer. Western blot (WB) validated the differential expression of TIA1 protein in bladder cancer and paracancerous tissues.

Survival analysis indicated that overall survival (P=0.00135), progression-free survival (P=0.00154) and disease-free survival (P=0.00116) were higher in the high TAI1 expression group than in the low expression one. TIA1 expression was obviously higher in the low age group (Age≤60 years) than in the high age group (P=0.007), and the higher the anatomical stage and T stage, the lower the TIA1 expression (P<0.01). COX regression analysis demonstrated that TIA1 (P=0.047), age (P<0.001), and anatomical stage (P<0.001) were independent prognostic factors for BLCA patients. The C-index of the nomogram was equal to 0.661 (0.619-0.704), which suggested that this model had a good predictive capacity. GSEA analysis demonstrated that TIA1 was abundant in "KEGG-Bladder cancer" and "KEGG-natural killer cell-mediated cytotoxicity" related pathways. WB assays also demonstrated that TIA1 protein expression was lower in BLCA tissues than in paracancerous tissues.

TIA1 gene expression is down-regulated in bladder cancer tissues, which may be an independent prognostic factor for the development of BLCA. The prognostic model constructed by TIA1 gene, age and clinical stage have a good predictive ability for progression-free survival of BLCA patients.