Lower Plasma Mir-92a Levels Predict Shorter Progression-Free Survival In Newly Diagnosed Symptomatic Multiple Myeloma Patients

Abstract

BackgroundCurrent prognostic model for multiple myeloma (MM) is based on International Staging System (ISS) and presence of specific chromosomal abnormalities (CAs), especially by fluorescence in situ hybridization (FISH) analysis. MicroRNAs (miRNAs) play important roles in the development and progression in multiple myeloma (MM). Previously, we have described that plasma miRNA profiling has showed considerably lower plasma miR-92a levels in newly diagnosed MM patients (Yoshizawa et al. Blood Cancer Journal 2(1):e53, 2012). The aim of this study was to investigate the impact of plasma miR-92a levels to CAs and to prognosis in patients with newly diagnosed MM. Patients and methodsFrom April 2004 to December 2012, 60 patients with newly diagnosed symptomatic MM (median age, 66 years; range, 34-93 years) were included in this study. We measured plasma miR-92a values (miR-92a/miR-638) by qRT-PCR. They were divided into high-risk and standard-risk by using FISH and conventional cytogenetic studies: high-risk cytogenetics was defined as translocations t(4;14), t(14;16), or del (17p13) detected by FISH, or del (13q) by Q-banding according to IMWG guidelines. All others, including t(11;14), were defined as standard-risk cytogenetics. We analyzed the clinical relevance of plasma miR-92a levels with respects to CAs. Furthermore we identified miR-92a expression cut points with the most impact on outcome to investigate which of the some disease characteristics and its cut-off value had prognostic influence in MM patients. ResultsChromosomal aberrations were noted in 26 (43%) MM patients after diagnosis, including 12 patients with t(4;14), 5 with t(11;14), 3 with t(14;16), 2 with del (17p13), 2 with del (13q), and 1 with t(4;14) and del (17p13), 1 with t(11;14) and del (17p13). Between MM patients with and without high-risk cytogenetics, there were no significant differences in β2-microglobulin and albumin levels (P = 0.994 and 0.85, respectively), ISS staging (P = 0.583), age (P = 0.651), sex (P = 0.585), frequency of CRAB symptoms (hypercalcemia, P = 0.755; renal insufficiency, P = 0.75; anemia, P = 0.375; bone lesion, P= 0.65, respectively). The plasma miR-92a level was significantly lower in the newly diagnosed MM with high-risk groups than in those with standard-risk groups (P = 0.015). Patients with plasma miR-92a levels < 0.04 had a significantly shorter progression-free survival (PFS) than patients with plasma miR-92a levels ≥ 0.04 (median PFS: 48 vs 15.8 months, P = 0.011). In addition, some clinical parameters were associated with adverse PFS: high-risk cytogenetics (P = 0.001), high proportions of bone marrow plasma cells (P = 0.043), high levels of serum β2-microglobulin (P = 0.022) and not attaining ≥ very good partial response (VGPR) (P = 0.007). On multivariate analysis, lower miR-92a level was an independent prognostic factor for PFS. Using the same miR-92a cut points, there was a tendency towards significant difference among standard-risk myeloma patients (P = 0.077). Moreover, the combinations of chromosomal aberrations and plasma miR-92a were able to classify newly diagnosed MM patients with three risk groups with different probabilities. ConclusionThe plasma miR-92a values vary across high- and standard-risk cytogenetics in newly diagnosed MM patients. We conclude that measurement of plasma miR-92a levels may not only function as novel biomarkers for diagnosis, but may also be helpful for prognostic stratification. Disclosures:Ohyashiki:Janssen Pharmaceutical co.: Research Funding.