PTP4A3 Independently Predicts Metastasis and Survival in Upper Tract Urothelial Carcinoma Treated with Radical Nephroureterectomy.

PURPOSE: Increasing evidence has shown that protein tyrosine phosphatases have dominant roles in setting the levels of tyrosine phosphorylation and promoting oncogenic processes. PTP4A3 has been implicated in cancer metastasis but to our knowledge the role of PTP4A3 in upper tract urothelial carcinoma is unknown. The aim of this study was to investigate the association of PTP4A3 with disease characteristics, distant metastasis and prognosis of upper tract urothelial carcinoma.

MATERIALS AND METHODS: The importance of PTP4A3 was initially examined in paired normal urothelium, noninvasive upper tract urothelial carcinoma, invasive upper tract urothelial carcinoma and nodal metastatic tissue. The PTP4A3 transcript level was assessed in another 20 upper tract urothelial carcinoma samples by real-time reverse transcriptase-polymerase chain reaction. PTP4A3 protein expression was determined by immunohistochemistry using the H-score in 340 upper tract urothelial carcinoma samples. It was further correlated with clinicopathological factors, and disease specific and metastasis-free survival.

RESULTS: The expression of PTP4A3 significantly increased from normal urothelium, noninvasive upper tract urothelial carcinoma and invasive upper tract urothelial carcinoma to nodal metastatic tissue (p <0.001). The PTP4A3 transcript level was also markedly up-regulated in higher stage upper tract urothelial carcinoma (p = 0.002). Over expression of PTP4A3 protein was significantly associated with advanced pT status, nodal metastasis, lymphovascular invasion and perineural invasion (each p <0.001) as well as with inferior disease specific and metastasis-free survival on multivariate analysis (each p <0.0001). In addition, it predicted metastasis in patients with pTa, pT1 and pT2 upper tract urothelial carcinoma.

CONCLUSIONS: Results imply that PTP4A3 has a role in the carcinogenesis of upper tract urothelial carcinoma. PTP4A3 over expression independently predicted the metastasis and outcome of upper tract urothelial carcinoma, which was even more important in organ confined disease.