Mutation analysis of NF-κB signal pathway-related genes in ocular MALT lymphoma.

Constitutive nuclear factor-kappa B (NF-κB) activation has been reported in ocular adnexal lymphoma (OAL). TNFAIP3/A20 is a "global" inhibitor of NF-κB pathway. We have shown that OAL has preferential loss of the 6q23.3 region where TNFAIP3/A20 exist, which is suggested to involve in lymphomagenesis of OAL. The mechanisms causing NF-κB activity in OAL remain elusive. Recently, NF-κB canonical pathway genes including CARD11, CD79B and MYD88 were shown to be frequently mutated in diffuse large B-cell lymphomas. In this study, we analyzed the mutation status of these genes by direct sequencing in 24 OAL cases including 9 cases with loss of 6q23.3 previously identified by array comparative genomic hybridization. We showed that genetic alterations of these genes were not found in OAL, a finding differing from that of most B-cell lymphomas. Genetic or epigenetic alterations in other genes are likely to be relevant in pathogenesis of OAL case without A20 loss.