Pediatric Hodgkin Lymphoma in 2 South American Series: A Distinctive Epidemiologic Pattern and Lack of Association of Epstein-Barr Virus With Clinical Outcome

Abstract

Hodgkin lymphoma (HL) shows a bimodal distribution with a first peak in developing countries during childhood. The causative role and prognostic significance of Epstein-Barr virus (EBV) association in patients with HL is controversial. Our aim was to perform a comparative study of EBV association in 2 Latin American pediatric HL series, and to correlate it with patient's survival. Epstein-Barr encoded RNAs in situ hybridization and latent membrane protein 1 immunohistochemistry were performed on formalin-fixed, paraffin-embedded HL biopsies from 176 pediatric patients from 2 public institutions from Argentina and Southeast Brazil. Mixed cellularity subtype was prevalent in Argentine HL (Arg HL) (52%) and nodular sclerosis subtype in Brazilian HL (BR HL) (83%). EBV expression was detected in 52% of cases, namely 54% Arg HL and 48% Br HL. EBV was significantly associated with mixed cellularity subtype in both populations. In Arg HL, EBV positivity was significantly higher in patients ≤10 years (P=0.0011). Event-free survival did not attain statistical significance neither in Arg HL (P=0.5317), nor in Br HL (P=0.8321). Our results do not support EBV association stated for pediatric HL in developing countries. Correlation of younger age with EBV infection only in Argentine patients might be related to a different age background. In our pediatric series, EBV status cannot be used as prognostic factor.