RESUMO
PURPOSE: The aim of this study was to investigate whether mRNA expression of the apoptosis-associated genes, XAF1 and XIAP, in bladder cancer patients correlates with response to neoadjuvant treatment. METHODS: Gene expression was analyzed by a real-time quantitative PCR method in paired samples from 14 bladder cancer patients treated with a combination of neoadjuvant gemcitabine and cisplatin. The prognostic significance of XAF1 and XIAP mRNA expression as well as the correlation with several clinical and pathological findings were evaluated. RESULTS: The clinical response in the XAF1-high subset (n = 5) was remarkably higher compared with the XAF1-low subset (n = 9) (100% vs. 44.4%; P = 0.038). These results translated into a notably improvement of progression-free survival (PFS) in the XAF1-high subset (log-rank P = 0.012). In addition, patients in the XAF1-high subset had a 3.9-fold decreased chance of dying from the disease (hazard ratio for death (HR), 0.257; (CI 95%), 0.043-1.536, P = 0.036). When we evaluated the expression of XIAP, although an inverse correlation was found between expression and pathological response, there were no statistically significant associations with the clinical response, the length of PFS, and OS. CONCLUSIONS: This is one of the few studies to address the role of XAF1 in a clinical setting. The data presented here identify XAF1 as a novel predictive and prognostic factor in bladder cancer patients. Furthermore, our observations are in line with previous studies, which point towards XAF1 as a tumor-suppressor gene. Nonetheless, additional studies, both mechanistic and translational, are warranted and may help not only in corroborating the role of XAF1 as a prognostic marker, but also as a potential target for anticancer therapy.
