Clinical significance of expression of fibronectin 1 in bladder cancer

Abstract

Objective To investigate the expression of fibronectin 1 (FN1) in bladder cancer and explore its clinical significance. Methods Four gene microarray datasets of bladder cancer were downloaded from Gene expression omnibus (GEO). Microarrays with 55 superficial bladder cancer and 132 muscle-invasive bladder cancer tissues were used for analysis of FN1 expression. 59 bladder cancer specimens and 23 adjacent tissues (cohort 1) were used to validate FN1 expression by real-time fluorescent quantitative polymerase chain reaction (FQ-PCR). The correlation of FN1 expression with clinical features was analyzed in patients with bladder cancer. Results Bioinformatics analysis identified that FN1 expression in muscle-invasive bladder cancer tissues was significantly higher than in superficial bladder cancer (P<0.01). Our results revealed that the expression of FN1 was remarkably up-regulated in bladder cancer tissues as compared with adjacent non-tumor bladder tissues detected by FQ-PCR (P<0.01), and the expression of FN1 was higher in muscle-invasive bladder cancer than in superficial bladder cancer (P<0.01). Meanwhile, the expression of FN1 was associated with clinical stage (31.0% vs. 67.0%, P<0.05 for cohort 1 and 6.7% vs. 57.7%, P<0.05 for cohort GSE31684) and lymph node metastasis (27.8% vs. 71.4%, P<0.05 for cohort 1 and 64.0% vs. 27.7%, P<0.05 for cohort GSE31684). In GSE31684 cohort, the expression of FN1 RNA in recurrent cases was higher than in recurrence-free cases (63.9% vs. 40.4%, P<0.05). More importantly, patients with high expression levels of FN1 had a shorter overall survival (OS, P<0.05) and disease-free survival (P<0.05) time than those with low expression. Univariate and multivariate analysis showed that FN1 was a significant and independent prognostic predictor for OS of patients with bladder cancer (hazard ratio=1.724, 95%CI=1.004-2.958, P<0.05). Conclusion FN1, up-regulated in patients with bladder cancer, may serve as an independent prognostic predictor for bladder cancer patients. Key words: Bladder cancer; Fibronectin 1; Prognosis