Prognostic Values of MicroRNA-21 and Ki-67 in Diffuse Large B-Cell Lymphoma Patients: Egyptian Experience.

Background: MicroRNA-21 (miR-21) is a small non-coding RNA which influences tumorigenesis by inhibiting the expression of target genes. Ki-67 is a nucleolar antigen highly correlated with the rate of proliferating cells. In this study, we aimed to evaluate the prognostic impact of miR-21 and Ki-67 in DLBCL disease in a cohort of Egyptian patients.

Methods: We prospectively enrolled 53 newly diagnosed DLBCL patients. RT-PCR was used to evaluate the plasma expression levels of miR-21. Tissue Ki-67 was assessed using immunohistochemistry (IHC) of lymph node biopsy sections. Overall survival (OS) and progression free survival (PFS) were the primary outcomes.

Results: miR-21 expression was significantly higher in patients with DLBCL in comparison to controls (p < 0.001). The median Ki-67 expression was 70% and positivity ranged from 25% to 100%. Response to treatment was achieved in 23 patients (43.4%). Higher miR-21 was associated with poor response to treatment (p = 0.03). Although patients' age was a significant predictor of OS in univariate analysis, none of the studied factors could predict OS in multivariate analysis. However, we found that Ki-67 expression was a significant predictor of PFS in both univariate and multivariate analyses.

Conclusions: The study suggested that plasma miR-21 might be a valuable non-invasive prognostic marker of response to treatment in DLBCL patients. Moreover, Ki-67 is a potential significant predictor of both OS and PFS in those patients.