Prognostic impact of gene expression-based classification for neuroblastoma

Purpose: To evaluate the impact of a predefined gene expression - based classifier for clinical risk estimation and cytotoxic treatment decision making in neuroblastoma patients.Patients and Methods: Gene expression profiles of 440 internationally collected neuroblastoma specimens were investigated by microarray analysis, 125 of which were examined prospectively. Patients were classified as either favorable or unfavorable by a 144- gene prediction analysis for microarrays (PAM) classifier established previously on a separate set of 77 patients. PAM classification results were compared with those of current prognostic markers and risk estimation strategies.Results: The PAM classifier reliably distinguished patients with contrasting clinical courses (favorable [n = 249] and unfavorable [n = 191]; 5- year event free survival [EFS] 0.84 +/- 0.03 v 0.38 +/- 0.04; 5-year overall survival [OS] 0.98 +/- 0.01 v 0.56 +/- 0.05, respectively; both P = .001). Moreover, patients with divergent outcome were robustly discriminated in both German and international cohorts and in prospectively analyzed samples (P = .001 for both EFS and OS for each). In subgroups with clinical low-, intermediate-, and high-risk of death from disease, the PAM predictor significantly separated patients with divergent outcome (low-risk 5-year OS: 1.0 v 0.75 +/- 0.10, P = .001; intermediaterisk: 1.0 v 0.82 +/- 0.08, P = .042; and high-risk: 0.81 +/- 0.08 v 0.43 = 0.05, P=.001). In multivariate Cox regression models based on both EFS and OS, PAM was a significant independent prognostic marker (EFS: hazard ratio [HR], 3.375; 95% CI, 2.075 to 5.492; P=.001; OS: HR, 11.119, 95% CI, 2.487 to 49.701; P=.001). The highest potential clinical impact of the classifier was observed in patients currently considered as non - high- risk (n= 289; 5- year EFS: 0.87= 0.02 v 0.44= 0.07; 5- year OS: 1.0 v 0.80= 0.06; both P=.001).Conclusion: Gene expression - based classification using the 144- gene PAM predictor can contribute to improved treatment stratification of neuroblastoma patients.Purpose: To evaluate the impact of a predefined gene expression - based classifier for clinical risk estimation and cytotoxic treatment decision making in neuroblastoma patients.Patients and Methods: Gene expression profiles of 440 internationally collected neuroblastoma specimens were investigated by microarray analysis, 125 of which were examined prospectively. Patients were classified as either favorable or unfavorable by a 144- gene prediction analysis for microarrays (PAM) classifier established previously on a separate set of 77 patients. PAM classification results were compared with those of current prognostic markers and risk estimation strategies.Results: The PAM classifier reliably distinguished patients with contrasting clinical courses (favorable [n = 249] and unfavorable [n = 191]; 5- year event free survival [EFS] 0.84 +/- 0.03 v 0.38 +/- 0.04; 5-year overall survival [OS] 0.98 +/- 0.01 v 0.56 +/- 0.05, respectively; both P = .001). Moreover, patients with divergent outcome were robustly discriminated in both German and international cohorts and in prospectively analyzed samples (P = .001 for both EFS and OS for each). In subgroups with clinical low-, intermediate-, and high-risk of death from disease, the PAM predictor significantly separated patients with divergent outcome (low-risk 5-year OS: 1.0 v 0.75 +/- 0.10, P = .001; intermediaterisk: 1.0 v 0.82 +/- 0.08, P = .042; and high-risk: 0.81 +/- 0.08 v 0.43 = 0.05, P=.001). In multivariate Cox regression models based on both EFS and OS, PAM was a significant independent prognostic marker (EFS: hazard ratio [HR], 3.375; 95% CI, 2.075 to 5.492; P=.001; OS: HR, 11.119, 95% CI, 2.487 to 49.701; P=.001). The highest potential clinical impact of the classifier was observed in patients currently considered as non - high- risk (n= 289; 5- year EFS: 0.87= 0.02 v 0.44= 0.07; 5- year OS: 1.0 v 0.80= 0.06; both P=.001).Conclusion: Gene expression - based classification using the 144- gene PAM predictor can contribute to improved treatment stratification of neuroblastoma patients.A