Whereas transcriptional silencing of genes due to epigenetic mechanisms is one of the most important alterations in acute lymphoblastic leukemia (ALL), some recent studies indicate that DNA methylation contributes to down-regulation of miRNAs during tumorigenesis. To explore the epigenetic alterations of miRNAs in ALL, we analyzed the methylation and chromatin status of the miR-124a loci in ALL. Expression of miR-124a was down-regulated in ALL by hypermethylation of the promoter and histone modifications including decreased levels of 3mk4H3 and AcH3 and increased levels of 2mK9H3, 3mK9H3, and 3mK27H3. Epigenetic down-regulation of miR-124a induced an up-regulation of its target, CDK6, and phosphorylation of retinoblastoma (Rb) and contributed to the abnormal proliferation of ALL cells both in vitro and in vivo. Cyclin-dependent kinase 6 (CDK6) inhibition by sodium butyrate or PD-0332991 decreased ALL cell growth in vitro, whereas overexpression of pre-miR124a led to decreased tumorigenicity in a xenogeneic in vivo Rag2 were analyzed in a group of 353 patients diagnosed with ALL. Methylation of hsa-miR-124a was observed in 59% of the patients, which correlated with down-regulation of miR-124a (P < 0.001). Furthermore, hypermethylation of hsa-miR-124a was associated with higher relapse rate (P = 0.001) and mortality rate (P < 0.001), being an independent prognostic factor for disease-free survival (P < 0.001) and overall survival (P = 0.005) in the multivariate analysis. These results provide the grounds for new therapeutic strategies in ALL either targeting the epigenetic regulation of microRNAs and/or directly targeting the CDK6-Rb pathway.

Acute myeloid leukemias (AMLs) result from multiple genetic alterations in hematopoietic stem cells. We describe a novel t(12;18)(p13;q12) involving ETV6 in a patient with AML. The translocation resulted in overexpression of SETBP1 (18q12), located close to the breakpoint. Overexpression of SETBP1 through retroviral insertion has been reported to confer growth advantage in hematopoietic progenitor cells. We show that SETBP1 overexpression protects SET from protease cleavage, increasing the amount of full-length SET protein and leading to the formation of a SETBP1-SET-PP2A complex that results in PP2A inhibition, promoting proliferation of the leukemic cells. The prevalence of SETBP1 overexpression in AML at diagnosis (n ‫؍‬ 192) was 27.6% and was associated with unfavorable cytogenetic prognostic group, monosomy 7, and EVI1 overexpression (P < .01). Patients with SETBP1 overexpression had a significantly shorter overall survival, and the prognosis impact was remarkably poor in patients older than 60 years in both overall survival (P ‫؍‬ .015) and event-free survival (P ‫؍‬ .015). In summary, our data show a novel leukemogenic mechanism through SETBP1 overexpression; moreover, multivariate analysis confirms the negative prognostic impact of SETBP1 overexpression in AML, especially in elderly patients, where it could be used as a predictive factor in any future clinical trials with PP2A activators. (Blood. 2010;115: 615-625)

ASCT constitutes a therapeutic option for HL patients after a first relapse. Promising results are observed in patients with low tumour burden at diagnosis, autografted after a long CR and without detectable disease at ASCT. Innovative approaches should be pursued for patients with risk factors at relapse.

ASCT achieves long-term disease-free survival in HD patients. Disease status before ASCT is the most important prognostic factor for final outcome; thus, transplantation should be considered in early stages of the disease. TBI must be avoided in the conditioning regimen because of a significantly higher rate of late complications, including secondary malignancies.

MSC expansion procedure, cell characterization and obtaining platelet lysate were performed according to standard procedures and are shown in the Online Supplementary Appendix. Patients' characteristics and MSC infusionOverall, 18 patients diagnosed with either acute (n=10) or chronic (n=8) GVHD refractory to prior treatment were included in the study once written informed consent had been obtained. Refractory GVHD was defined as progression or absence of response to last treatment. Patients' characteristics are summarized in Table 2. Eleven patients had received reduced intensity conditioning and 6 received myeloablative conditioning. Fourteen patients had received hematopoietic stem cells from an unrelated donor and 7 received them from an HLA-mismatched donor. Eight patients had received GVHD prophylaxis based on a calcineurin inhibitor plus methotrexate.Inclusion criteria were: patients who had undergone an allogeneic stem cell transplant and developed GVHD refractory to conventional treatment; adequate cardiac and pulmonary functions; aged between 18 and 65 years; signed informed consent from patient and donor. Exclusion criteria were: patients who did not fulfill all of the inclusion criteria; progression of the hematologic disease; active infection; women who were either pregnant or at risk of pregnancy. The study was conducted between February 2007 and December 2009.Patients received 1-2x10 6 MSCs/kg intravenously in a single dose. Eventually, when a partial response was obtained or in the case of relapse after achieving complete remission, patients could receive a second dose of MSCs at least two weeks after the first infusion. Patients who were receiving 6-methylprednisolone were kept on the same doses for at least seven days after MSC infusion and a taper of 10% every five days was planned later when there was a response. Other immunosuppressive drugs were managed according to the criteria of the attending physician. Response to therapy was measured according to previously reported criteria. [9][10][11] Patients were taken off the study if fewer than 1x10 6 MSCs/kg were obtained after eight weeks of expansion. All patients receiving at least one dose of MSCs were included in the safety and efficacy analysis.The treatment protocol was reviewed and approved by the local authorities and ethical committee of all participanting centers.Mesenchymal cells for graft vs. host disease treatment haematologica | 2011; 96 (7) 1073 Statistical analysisVariables of the expansion procedure were analyzed from the day of inclusion in the trial, i.e. the day when informed consent was signed. Mean and median values and their corresponding 95% confidence intervals (CIs) and ranges were calculated for each continuous variable. Student's two-sample t test and Pearson's X 2 test were used to compare continuous and qualitative variables. In those comparisons where the number of cases precluded the use of parametric tests, the Mann-Whitney test and Fisher's exact test were used. To analyze patient outcome after infusi...