OBJECTIVETo study the expression of miR-146b-5p in diffuse large B cell lymphoma (DLBCL), and its relationship with risk assessment.

METHODS62 cases of nodal DLBCL with follow-up data were collected from Shanxi Cancer Hospital, and were studied by using immunohistochemical EnVision method for CD3, CD10, CD20, Bcl-6 and MUM1. The DLBCLs were classified into germinal center B cell-like (GCB) and non-germinal center B cell-like (non-GCB) subtypes according to Hans'algorithm. Agilent Human miRNA Microarray 16.0 was used to select the miRNAs on paraffin-embedded tissues of 24 DLBCL cases. A TaqMan real-time polymerase chain reaction (RT-PCR) method was performed on 62 nodal DLBCL cases to validate the expression levels of miR-146b-5p.11 cases with reactive lymph node were elected as control.

RESULTSIn 62 cases of DLBCL, 35.5% of cases were GCB and 64.5% non-GCB subtypes, the expression of miR-146b-5p in GCB was 3.2 times as much as non-GCB subtypes (P = 0.006). The expression of miR-146b-5p was up-regulated in DLBCL, and expression level of miR-146b-5p was 5.4 times as much as reactivated lymph node. In 62 cases of DLBCL, 43.5% cases were recurrence-free and 56.5% recurrence. The expression of miR-146b-5p was remarkably up-regulated in recurrence-free group compared with recurrence group (P = 0.004). Moreover, high expression levels of miR-146b-5p in DLBCL were found to be associated with longer relapse-free survival (P = 0.005), but not for overall survival. Multivariate COX proportional hazard regression analysis revealed that low expression of miR-146b-5p (P = 0.004) and IPI ≥ 3(P = 0.011) were independent poor prognostic factors in 62 cases of DLBCL.

CONCLUSIONSThe expression of miR-146b-5p was up-regulated in recurrence-free group, and its higher expression levels in DLBCL were associated with improved relapse-free survival. Our results suggested that miR-146b-5p might be one of markers for risk assessment.