Purpose: Despite major advances in the treatment of diffuse large B cell lymphoma (DLBCL), approximately one third of the patients progress or die, suggesting the existence of additional oncogenic events. The purpose of this study was to evaluate the prognostic value of the "Hans classifier", and BCL2 and MYC protein expression and gene alterations in DLBCL patients treated with CHOP or R-CHOP chemotherapy over a 5-year period. Furthermore, we tried to correlate these parameters with the International Prognostic Index (IPI).
Methods: The immunohistochemical (IHC) expression of CD10, BCL6, MUM1 and BCL2 on paraffin-embedded formalin-fixed tumor samples from 103 centroblastic DLBCLs was analyzed. IHC expression of MYC and fluorescence in situ hybridization (FISH) for MYC and BCL2 gene alterations was performed on 67 samples using the tissue microarray (TMA) method.
Results: The Hans algorithm was not predictive of survival in both therapy groups. No significant difference in BCL2 and MYC alterations or MYC protein expression in relation to complete response (CR), event-free survival (EFS) and overall survival (OS) was observed in our study. High IPI correlated significantly with poor outcome and it was identified as independent prognostic factor for OS and EFS (both p=0.000). The 5-year OS was 61% in the R-CHOP compared to 38% in the CHOP group (p=0.007). Rituximab significantly improved the OS in the BCL2 positive (60 vs 29%, p=0.008), and the BCL6 negative (73 vs 25%, p=0.001) cases.
Conclusion: IPI is an independent prognosticator for DL-BCL patients and the addition of rituximab significantly improved survival. Furthermore, patients with BCL2+ and BCL6-DLBCL benefited from R-CHOP.