Objectives: The aim of this study was to test choline-phosphate cytidylyltransferase-α (CCT-α) protein as a biomarker for neoadjuvant cisplatin chemotherapy response in a bladder tumor setting.
Materials and methods: A total of 238 patients with T2-T4 bladder cancer enrolled into two prior randomized trials comparing neoadjuvant cisplatin-based chemotherapy (NAC) plus cystectomy with cystectomy only (no-NAC) were used as discovery and validation cohorts. Protein expression was determined with immunohistochemistry and assessed with Histo (H)-scoring.
Results: In the discovery cohort, comprising 61 patients, the survival ratio after NAC treatment for CCT-α-negative patients was significantly increased (p = 0.001) while there was no survival advantage in the CCT-α-positive patient group. Similarly, in the validation cohort with 177 patients, NAC treatment improved survival only in the CCT-α-negative group (p = 0.006). Although there was a tendency for a good NAC response with negative CCT-α status, the interaction variable between biomarker and treatment was not significant (p = 0.24). In the cystectomy-only group, patients with positive CCT-α expression had a better survival than CCT-α-negative patients. This prognostic effect of CCT-α expression remained significant after adjusting for well-known prognostic factors in a multivariate analysis. In a pooled database of both patient data sets, multivariate analyses showed CCT-α status as an independent factor for overall survival (p = 0.018; hazard ratio = 1.80, 95% confidence interval 1.11-2.93).
Conclusion: CCT-α status was not predictive of outcome of NAC response; however, in the control group with cystectomy only it was found to have prognostic value.
Keywords: Biomarker; bladder cancer; choline-phosphate cytidylyltransferase-α; neoadjuvant cisplatin; predictive; prognostic.