Background: The role of microRNAs (miRNAs) in multiple myeloma (MM) has yet to be fully elucidated. To identify miRNAs that are potentially deregulated in MM, we investigated those mapping within transcription units, based on evidence that intronic miRNAs are frequently coexpressed with their host genes. To this end, we monitored host transcript expression values in a panel of 20 human MM cell lines (HMCLs) and focused on transcripts whose expression varied significantly across the dataset. Methods: miRNA expression was quantified by Quantitative Real-Time PCR. Gene expression and genome profiling data were generated on Affymetrix oligonucleotide microarrays. Significant Analysis of Microarrays algorithm was used to investigate differentially expressed transcripts. Conventional statistics were used to test correlations for significance. Public libraries were queried to predict putative miRNA targets. Results: We identified transcripts specific to six miRNA host genes (CCPG1, GULP1, EVL, TACSTD1, MEST, and TNIK) whose average changes in expression varied at least 2-fold from the mean of the examined dataset. We evaluated the expression levels of the corresponding intronic miRNAs and identified a significant correlation between the expression levels of MEST, EVL, and GULP1 and those of the corresponding miRNAs miR-335, miR-342-3p, and miR-561, respectively. Genome-wide profiling of the 20 HMCLs indicated that the increased expression of the three host genes and their corresponding intronic miRNAs was not correlated with local copy number variations. Notably, miRNAs and their host genes were overexpressed in a fraction of primary tumors with respect to normal plasma cells; however, this finding was not correlated with known molecular myeloma groups. The predicted putative miRNA targets and the transcriptional profiles associated with the primary tumors suggest that MEST/miR-335 and EVL/miR-342-3p may play a role in plasma cell homing and/or interactions with the bone marrow microenvironment. Conclusion: Our data support the idea that intronic miRNAs and their host genes are regulated dependently, and may contribute to the understanding of their biological roles in cancer. To our knowledge, this is the first evidence of deregulated miRNA expression in MM, providing insights that may lead to the identification of new biomarkers and altered molecular pathways of the disease.

Introduction: Multiple myeloma (MM) is characterized by a high prevalence of thrombotic complications. Microvesicles (MVs) are small membrane vesicles released from activated cells, and they may potentially contribute to thrombosis. Methods: We have evaluated the plasma levels of MVs and cytokines (IL-10, IL-17, and TGF-β in MM and Watch and Wait Smoldering MM (WWSMM) from patients and related them to thrombotic complications. The secondary aim was to assess the impact of ongoing therapy on MV and on cytokine levels. Result: 92 MM and 31 WWSMM were enrolled, and 14 (12%) experienced a thrombotic episode. Using univariate analysis, TGF-β and MV were significantly higher in patients with thrombotic events (p = 0.012; p = 0.008, respectively). Utilizing a Cox proportional hazard model, we confirmed this difference (TGF-β p = 0.003; Odds ratio 0.001, 95% CI 0–0.003 and MV p = 0.001; Odds ratio 0.003, 95% CI 0.001–0.005). Active treatment management displayed higher levels of MV (p < 0.001) and lower levels of glomerular filtration-rate (p < 0.001), IL-17 (p < 0.001) as compared to the WWSMM group. The TGF-β values of immunomodulatory derivatives patients were lower in the WWSMM (p < 0.001) and Dexamethasone/Bortezomib subgroup (p < 0.001). Conclusion: The increased levels of MVs in active regimens add insight into the mechanisms of hypercoagulation in MM. In addition, a role for cytokine-related thrombosis is also suggested.

Although high-dose cyclophosphamide (HD-CTX) is commonly used as a mobilising regimen for autologous peripheral blood stem cell (PBSC) collection, significant morbidity and insufficient harvesting may complicate the procedure. Alternative regimens and lower doses of cyclophosphamide (CTX) have been investigated as possible ways of overcoming these difficulties. Low-dose CTX (1.5 g/m2) was administered to 102 lymphoma patients as an autologous PBSC mobilising regimen. The collection of 6 x 10(6) CD34+ cells/kg was chosen as the target of the apheresis sessions, whereas 3 x 10(6)/kg were considered the minimum necessary to perform autologous stem cell transplantation (ASCT) safely. The apheretic sessions were started a median of eight days after CTX administration; a median of two aphereses was required. More than 6 x 10(6) CD34+ cells/kg were collected from 78 patients, between 3 and 6 x 10(6)/kg from 19, and fewer than 3 x 10(6)/kg from 5, two of whom underwent bone marrow harvesting and one a successful second PBSC harvesting session using the same mobilising regimen. Eighty-two patients underwent autografting, six of whom received a second transplant after relapse (five using autologous PBSCs coming from the first apheretic course). Low-dose CTX proved to be a safe and effective regimen for autologous PBSC mobilization and also compared favourably with alternative regimens in terms of the rate of harvesting insufficiency. This does not imply that low-dose CTX is the best mobilising regimen for all patients, and the identification of prognostic factors predicting mobilising potential may help in choosing the best individualised regimen.