MicroRNAs as novel biomarkers in diffuse large B-cell lymphoma - a systematic review

INTRODUCTION: MicroRNAs (miRNAs) are short non-coding RNAs that have the ability to regulate gene expression at the post-transcriptional level. MiRNAs are deregulated in many cancer types, and several miRNAs have been suggested as novel diagnostic and prognostic biomarkers in diffuse large B-cell lymphoma (DLBCL). The objective of this study was to systematically collect and evaluate current knowledge of miRNAs functioning as diagnostic and prognostic biomarkers within DLBCL. METHODS: This review was conducted according to the Preferred Reporting for Systematic Reviews and Meta-analyses guidelines. A systematic search of literature in PubMed and Embase was made and supplemented by screening of reference lists. Only original peer-reviewed studies written in English were included and screened based on miRNA expression, molecular subtypes of DLBCL and patient outcome. RESULTS: Out of 277 candidate records, a total of 20 studies qualified for inclusion in this review. In all, 11 studies reported a total of 48 miRNAs with expression patterns associated with specific molecular DLBCL subtypes, and 14 studies reported a total of 30 miRNAs associated with patient outcome. However, only few miRNAs showed significant results in more than one study. CONCLUSION: MiRNAs qualify as potential diagnostic and prognostic biomarkers in DLBCL. However, more clinical validation including prospective and cross-centre studies are required before specific miRNAs can be integrated into the daily practice as biomarkers in DLBCL, which would contribute to an era of more personalised medicine.