Down-regulation of PDCD4 expression is an independent predictor of poor prognosis in human renal cell carcinoma patients.

OBJECTIVES: The tumor suppressor gene entitled programmed cell death 4 (PDCD4) encodes a protein that inhibits neoplastic transformation and invasion. The aim of this study was to investigate the expression of PDCD4 and its prognostic roles in human renal cell carcinoma (RCC). MATERIALS AND METHODS: A total of 32 paired fresh tumor specimens and adjacent non-cancerous renal tissue from RCC patients by western blot to detect the difference of PDCD4 expression in tumor tissues and non-cancerous tissues. 66 RCC paraffin-embedded specimens and 18 normal renal tissues were analyzed by immunohistochemistry to investigate the association of PDCD4 expression with RCC clinicopathological features. RESULTS: PDCD4 expression was significantly decreased in RCC compared with normal renal tissues (P = 0.03), and it was found to be significantly associated with RCC metastasis (P = 0.007), tumor T-stage (P = 0.022) and tumor grade (P = 0.015). The mean overall survival was significantly decreased in the low PDCD4 group compared to the high PDCD4 group (low PDCD4: mean overall survival 41.9 months, high PDCD4: mean overall survival 52.9 months, P = 0.008). CONCLUSION: PDCD4 expression strongly correlated to RCC stage, tumor grade, tumor metastasis and tumor-related death. PDCD4 expression was also appears to be a marker in RCC prognosis.