CXCL5 is a potential diagnostic and prognostic marker for bladder cancer patients.

Chemokine C-X-C motif ligand 5 (CXCL5) is critical for bladder cancer growth and progression. Our previous study demonstrated that increase of CXCL5 in bladder cancer cell lines had an effect on tumor growth and progression. This study aims to investigate the expression of CXCL5 in tissue and urine of bladder cancer patients, in relation to clinicopathologic parameters, and as a predictive value in diagnosing and evaluating bladder cancer. Urothelial bladder cancer tissues from 255 patients were profiled for CXCL5 alterations by immunohistochemistry. Urine samples collected from patients with bladder cancer and urinary tract infections as well as healthy volunteers were analyzed by ELISA. High expression of CXCL5 in bladder cancer tissue was correlated with TNM stage (P = 0.012), cancer grade (P = 0.001), and lymph node metastasis (P = 0.007). CXCL5 alterations were associated with overall survival (P = 0.007), progression free survival (P = 0.004), and recurrence free survival in muscle invasive bladder cancers (P = 0.026). CXCL5 expression in the urine of bladder cancer patients was significantly different from urinary tract infection patients (P = 0.001) and healthy volunteers. However, urine leukocytes may predict CXCL5 levels (β = 0.56, P < 0.001, R (2) = 0.314). CXCL5 expression in urine was also related to bladder cancer TNM stage (P = 0.039), lymph node metastasis (P = 0.023), tumor size (P = 0.007), and tumor grade (P = 0.005). The sensitivity and specificity for CXCL5/creatinine in predicting bladder cancer were 80.4 and 61.3 %, respectively. These results suggest increased CXCL5 expression in cancer tissue predicts poor survival in bladder cancer patients. CXCL5 expression in urine is useful in a minimally invasive modality for bladder cancer diagnosis. However, urine leukocytes are significant predictors of CXCL5 levels and may affect its result in bladder cancer diagnosis.