MYD88, CD79B, and CARD11 gene mutations in CD5-positive diffuse large B-cell lymphoma

CD5-positive (CD5⁺ ) diffuse large B-cell lymphoma (DLBCL) is characterized by frequent central nervous system recurrence and a predominant activated B-cell-like nature. Primary DLBCL in sanctuary sites (DLBCL-SS) also demonstrates these features, and >70% of patients harbor myeloid differentiation primary response 88 (MYD88) (L265P) and CD79B mutations. The objective of the current study was to elucidate a possible relationship between CD5⁺ DLBCL and DLBCL-SS.

MYD88, CD79B, CD79A, and caspase recruitment domain family member 11 (CARD11) mutations were examined in samples from 40 patients with CD5⁺ DLBCL. Mutation analysis was performed by direct sequencing.

MYD88 and CD79B mutations were detected in 33% (13 patients) and 38% (15 patients), respectively, of the 40 patients with CD5⁺ DLBCL. Ten patients had these 2 gene mutations, and 1 had a CD79A mutation. One of 2 patients with testicular involvement had both MYD88 and CD79B mutations. The other patient had a MYD88 mutation alone. None of the 31 patients examined was found to have a CARD11 mutation. MYD88 and CD79B mutations were found to be associated with localized disease (P = .038 and P = .003, respectively). Primary extranodal lymphoma was associated with higher frequencies of mutations in MYD88 or both MYD88 and CD79B (P = .008 and P = .014, respectively). There was no significant difference in overall survival based on MYD88 and CD79B mutation status.

The incidence of MYD88 and CD79B mutations in patients with CD5⁺ DLBCL is lower than that in patients with DLBCL-SS, suggesting that CD5⁺ DLBCL is not the same disease as DLBCL-SS in terms of gene mutation status. CARD11 mutations are rare in patients with CD5⁺ DLBCL. Cancer 2017;123:1166-1173. © 2016 American Cancer Society.