The prognostic importance of double-expressor subgroup and AID, UNG and mismatch repair protein expressions in diffuse large B-cell lymphomas

Objective: The cases of diffuse large B-cell lymphoma, (DLBCL not otherwise specified (NOS)) which immunohistochemicallyexhibit MYC and BCL2 expressions are defined as double-expressor lymphomas (DELs). This study aimed to assess the prognosticimpact of DEL and the expressions of other proteins that may have role in tumorogenesis.Materials and Methods: In this study, 90 tumor samples from patients diagnosed with DLBCL NOS were evaluated retrospectively.Immunoexpressions of MYC, BCL2, activation-induced cytidine deaminase (AID), uracil-DNA glycosylase (UNG) and DNAmismatch repair proteins including MLH1, MSH2, MSH6 and PMS2 were analyzed.Result: Eleven cases (12.2%) which exhibited ≥40% MYC and ≥50% BCL2 immunexpressions were classified as DEL DLBCL. Patientswith MYC positivity displayed lower overall survival rate than MYC negative cases. A trend of lower overall survival was observed inthe double-expressor lymphoma group, however, this was not proven to be statistically significant. Significant relationship betweenAID, UNG and p53 immunexpressions with double-expressor lymphoma or overall survival was not detected. The correlationbetween immunexpressions of p53 and MYC was observed. The loss of expression of mismatch repair proteins was not observed inany cases.Conclusion: In this study, a relationship between low overall survival and MYC expression is detected. However, our result does notdemonstrate that double-expressor lymphoma can be associated with poor outcomes.