Bcl-2 Gene Amplification and Protein Expression and Their Relationship with Clinicopathological Characteristics and Immunophenotype of Primary Gastrointestinal Diffuse Large B-cell Lymphoma / 胃肠病学

ABSTRACT

Background: Aberrant Bcl-2 transcription is closely related with nodal diffuse large B-cell lymphoma (DLBCL), however, the relationship between Bcl-2 and primary gastrointestinal DLBCL (PGI-DLBCL) was not fully studied.Aims: To investigate the relationship between Bcl-2 gene amplification and protein expression and clinicopathological characteristics, immunophenotype and prognosis of PGI-DLBCL.Methods: Clinical data was collected from 136 PGI-DLBCL patients receiving surgical treatment, and a telephone interview was conducted for survival information.Bcl-2 gene amplification and protein expression in tumor tissue were determined by fluorescence in situ hybridization and immuno-histochemistry, respectively, and relationships between Bcl-2 and clinicopathological characteristics, immunophenotype and prognosis of PGI-DLBCL were analyzed.Results: Among 136 PGI-DLBCL patients, 33 (24.3%) showing gene amplification and 90 (66.2%) showing protein expression of Bcl-2;gene amplification was correlated with primary tumor location, Ann Arbor stage, serum lactate dehydrogenase level, B symptom and International Prognostic Index (IPI) score (P<0.05), while protein expression was correlated with primary tumor location and immunophenotype (P<0.05).5-year overall survival (OS) in patients positive for Bcl-2 gene amplification and patients with non-GCB immunophenotype and positive for Bcl-2 protein expression were inferior to those negative ones (41.5%vs.71.5%, P<0.05;54.6% vs.84.6%, P<0.05).In Bcl-2 gene amplification or protein expression positive patients, 5-year OS of CHOP chemotherapy was inferior to that of rituximab combined with CHOP chemotherapy (48.6%vs.80.3%, P<0.05;66.4%vs.83.4%, P<0.05).Conclusions: Detection of Bcl-2 gene amplification is useful for prediction of prognosis in PGI-DLBCL.Both patients with Bcl-2 gene amplification and non-GCB patients with Bcl-2 protein expression have a poorer prognosis.Rituximab may improve the prognosis in patients with Bcl-2 gene amplification or protein expression.