Genomic Mutation Profile of Primary Gastrointestinal Diffuse Large B-Cell Lymphoma.

Primary gastrointestinal diffuse large B-cell lymphoma (GI-DLBCL) is the most common gastrointestinal lymphoma, but its genetic features are poorly understood. We performed whole-exome sequencing of 25 primary tumor samples from patients with GI-DLBCL and 23 matched normal tissue samples. Oncogenic mutations were screened, and the correlations between genetic mutations and clinicopathological characteristics were analyzed. Twenty-five patients with GI-DLBCL were enrolled in the genetic mutation analysis with a median of 184 (range 79-382) protein-altering variants per patient. We identified recurrent oncogenic mutations in GI-DLBCL, including those in , and . Compared with nodal DLBCL, GI-DLBCL exhibited an increased mutation frequency of and reduced mutation frequencies of , and . Moreover, GI-DLBCL exhibited fewer and mutations than DLBCL in the testis and central nervous system. GI-DLBCLs with , and mutations exhibited a tendency toward a high proliferation index. and mutations often occurred in tumors with early clinical staging. Our data provide a comprehensive understanding of the landscape of mutations in a small subset of GI-DLBCLs. The genetic mutation profiles of GI-DLBCL differ from those of nodal DLBCL and DLBCL in immune-privileged sites. The different mutated genes are related to the NF-κB and JAK-STAT pathways, and the different pathogenetic mechanisms leading to the development of DLBCL may be influenced by the tissue microenvironment. Differences in genetic alterations might influence the clinicopathological characteristics of GI-DLBCL.