In the present study, we aimed (i) to confirm previous findings of mGluR5 in cultured HL cells now in actual lymphoma tissue using a larger cohort of pediatric HL cases, (ii) to examine the frequency and localization of the antigen and (iii) to investigate a possible association of mGluR5 expression in tumor tissue with clinical features and disease progression. This evidence concerns the gene GRM5 and lymphoma.