Upregulation of Arp2 expression is associated with the prognosis and prediction of lymph node metastasis in bladder urothelial carcinoma.

Objective: Upregulation of actin-related protein 2/3 complex subunit 2 (Arp2) is observed in various tumors, but its expression pattern has not been revealed in bladder urothelial carcinoma (BUC). The purpose of this study was to investigate the role of Arp2 expression in the pathological features and the prognosis as well as lymph node metastasis of BUC.

Methods: A total of 228 tissue specimens from BUC patients who underwent a radical cystectomy were collected. In addition, 40 lymph node specimens and 40 normal bladder tissue specimens as controls were used. All of the specimens were used to construct a tissue microarray and were subsequently subjected to immunohistochemical staining for Arp2 expression. Logistic and Cox regression analyses and Kaplan-Meier curve analysis were applied to analyze the relation between Arp2 expression and multiple clinical features of patients with BUC.

Results: Immunohistochemical staining observation showed that Arp2 was mainly expressed in the cytoplasm and nucleus of positive cells and that Arp2 expression in BUC was significantly higher than that in normal bladder tissues. Arp2 expression in BUC tissues was associated with tumor size, tumor multiplicity, tumor stage, tumor grade, and lymph node metastasis ( P < 0.05). Logistic regression analysis demonstrated that Arp2 expression was an independent risk factor for lymph node metastasis of BUC ( P < 0.05). Kaplan-Meier curve analysis showed that increased Arp2 expression was associated with a shortened recurrence-free survival (RFS) and overall survival (OS) of BUC patients after radical cystectomy ( P < 0.05).

Conclusion: These findings suggest that Arp2 is significantly upregulated in BUC tissues when compared with normal bladder tissues, and that Arp2 expression is an independent predictor for lymph node metastasis, RFS, and OS.