Immunophenotype classification and therapeutic outcomes of Chinese primary gastrointestinal diffuse large B-cell lymphoma.

BACKGROUND: Recent studies showed that diffuse large B-cell lymphoma (DLBCL) could be classified into germinal centre B cell-like (GCB) and non-germinal centre B cell-like (non-GCB) phenotypes according to CD10,Bcl-6 and MUM1 expression. But primary gastrointestinal DLBCL has rarely been studied. This study was aimed to investigate the relationship between immunophenotypic classification, therapeutic outcomes and the prognosis of patients with primary gastrointestinal DLBCL.

METHODS: Between 1998 and 2010, there were 151 patients studied at Shanghai Renji Hospital with a histopathological diagnosis of primary gastrointestinal DLBCL. Immunohistochemistry was performed using EnVision methods for CD10, BCL-6 and MUM1. The clinicopathologic features and follow-up data were analyzed by the Kaplan-Meier method, log-rank test and χ2 test.

RESULTS: According to the expression of CD10, BCL-6 and MUM1, 31.8 % (48/151) of the cases belonged to the GCB subtype and 68.2 % (103/151) belonged to the non-GCB subtype. There was a significant difference of local lymph node metastasis between the GCB and non-GCB groups (P < 0.05). Patients in the GCB group had a better survival rate than those in the non-GCB group (5-year survival rate, 65.2 % vs 36.4 %, P < 0.05). In the GCB group, there was no significant difference in survival rates in patients receiving R-CHOP and CHOP therapy (P > 0.05). In the non-GCB group, the survival rate in patients treated with R-CHOP therapy was significantly longer than those treated with CHOP therapy (5-year survival rate, 62.8 % vs 30.8 %, P < 0.05).

CONCLUSIONS: The immunophenotype classification of gastrointestinal DLBCL, which is closely related to local lymph node metastasis, is found to have prognostic significance. Immunophenotype classification is also useful in selecting the chemotherapy protocol.