Downregulated expression of Dicer1 predicts inferior survival in primary gastrointestinal diffuse large B-cell lymphoma treated with CHOP-like regimen and rituximab.

The aim of this study was to detect the expression levels of Dicer1, Drosha, DGCR8, and Ago2 messenger ribonucleic acids (mRNAs) in patients with primary gastrointestinal diffuse large B-cell lymphoma (PGI-DLBCL) and determine their associations with clinical parameters and prognostic significance. The mRNA level expressions of Dicer1, Drosha, DGCR8, and Ago2 were detected by real-time quantitative polymerase chain reaction. Immunohistochemical staining of CD10, BCL6, and MUM1 was performed using EnVision™ system. The clinicopathologic features and follow-up data were analyzed using Kaplan-Meier estimator. The results show that the expression of Dicer1 (P=0.001), Drosha (P=0.01), DGCR8 (P=0.02), and Ago2 (P=0.002) mRNAs in cancer tissues of patients with PGI-DLBCL was significantly lower than those in normal tissues of healthy controls. Among the expression of CD10, BCL6, and MUM1, 27.4% (17/62) of the patients belonged to the germinal center B-cell (GCB) subtype and 72.6% (45/62) belonged to the non-GCB subtype. Dicer1 expression was significantly decreased in the non-GCB subgroup (P=0.02) and in the high International Prognostic Index (3-5 score) subgroup (P=0.03). Kaplan-Meier analysis showed that the low-Dicer1 subgroup had a shorter overall survival (P=0.02) and shorter progression-free survival (P=0.015) than the high-Dicer1 subgroup. Multivariate analysis identified Dicer1 as an independent prognostic factor in PGI-DLBCL. In Conclusion, Dicer1, Drosha, DGCR8, and Ago2 play key roles in the pathogenesis of PGI-DLBCL. Dicer1, an independent prognostic factor for predicting shortened survival of patients with PGI-DLBCL, can be used as a biomarker to guide the prognosis.