PURPOSE Assessing measurable residual disease (MRD) has become standard with many tumors, but the clinical meaning of MRD in multiple myeloma (MM) remains uncertain, particularly when assessed by next-generation flow (NGF) cytometry. Thus, we aimed to determine the applicability and sensitivity of the flow MRD-negative criterion defined by the International Myeloma Working Group (IMWG). PATIENTS AND METHODS In the PETHEMA/GEM2012MENOS65 trial, 458 patients with newly diagnosed MM had longitudinal assessment of MRD after six induction cycles with bortezomib, lenalidomide, and dexamethasone (VRD), autologous transplantation, and two consolidation courses with VRD. MRD was assessed in 1,100 bone marrow samples from 397 patients; the 61 patients without MRD data discontinued treatment during induction and were considered MRD positive for intent-to-treat analysis. The median limit of detection achieved by NGF was 2.9 × 10−6. Patients received maintenance (lenalidomide ± ixazomib) according to the companion PETHEMA/GEM2014MAIN trial. RESULTS Overall, 205 (45%) of 458 patients had undetectable MRD after consolidation, and only 14 of them (7%) have experienced progression thus far; seven of these 14 displayed extraosseous plasmacytomas at diagnosis and/or relapse. Using time-dependent analysis, patients with undetectable MRD had an 82% reduction in the risk of progression or death (hazard ratio, 0.18; 95% CI, 0.11 to 0.30; P < .001) and an 88% reduction in the risk of death (hazard ratio, 0.12; 95% CI, 0.05 to 0.29; P < .001). Timing of undetectable MRD (after induction v intensification) had no impact on patient survival. Attaining undetectable MRD overcame poor prognostic features at diagnosis, including high-risk cytogenetics. By contrast, patients with Revised International Staging System III status and positive MRD had dismal progression-free and overall survivals (median, 14 and 17 months, respectively). Maintenance increased the rate of undetectable MRD by 17%. CONCLUSION The IMWG flow MRD-negative response criterion is highly applicable and sensitive to evaluate treatment efficacy in MM.

Patients with multiple myeloma (MM) carrying high-risk cytogenetic abnormalities (CA) have inferior outcome despite achieving similar complete response (CR) rates when compared to cases with standard-risk CA. This questions the legitimacy of CR as treatment endpoint for high-risk MM, and represents a biological conundrum regarding the nature of tumor reservoirs persisting after therapy in patients with standard- and high-risk CA. Here, we used next-generation flow (NGF) to evaluate measurable residual disease (MRD) in MM patients with standard- (N=300) vs high-risk CA (N=90) enrolled in the PETHEMA/GEM2012MENOS65 trial (NCT01916252), and to identify mechanisms determining MRD resistance in both patient subgroups (N=40). The 36-month progression-free and overall survival rates were higher than 90% in patients with undetectable MRD, with no significant differences (P≥0.202) between cases having standard- vs high-risk CA. Persistent MRD resulted in median progression-free survival of approximately three and two years in patients with standard- and high-risk CA, respectively (P&lt;0.001). Further use of NGF to isolate MRD followed by whole-exome sequencing of paired diagnostic and MRD tumor cells, revealed greater clonal selection in patients with standard-risk CA, higher genomic instability with acquisition of new mutations in high-risk MM, and no unifying lost or acquired genetic abnormalities driving MRD resistance. Conversely, RNA sequencing of diagnostic and MRD tumor cells uncovered the selection of MRD clones with singular transcriptional programs and ROS-mediated MRD resistance in high-risk MM. Our study supports undetectable MRD as treatment endpoint for MM patients with high-risk CA and proposes characterizing MRD clones to understand and overcome MRD resistance.

Mesenchymal stem cell (MSC) transplantation is emerging as an ideal tool to restore the wounded central nervous system (CNS). MSCs isolated from extra-embryonic tissues have some advantages compared to MSCs derived from adult ones, such as an improved proliferative capacity, life span, differentiation potential and immunomodulatory properties. In addition, they are more immunoprivileged, reducing the probability of being rejected by the recipient. Umbilical cords (UCs) are a good source of MSCs because they are abundant, safe, non-invasively harvested after birth and, importantly, they are not encumbered with ethical problems. Here we show that the intravitreal transplant of Wharton´s jelly mesenchymal stem cells isolated from three different human UCs (hWJMSCs) delays axotomy-induced retinal ganglion cell (RGC) loss. In vivo, hWJMSCs secrete anti-inflammatory molecules and trophic factors, the latter alone may account for the elicited neuroprotection. Interestingly, this expression profile differs between naive and injured retinas, suggesting that the environment in which the hWJMSCs are modulates their secretome. Finally, even though the transplant itself is not toxic for RGCs, it is not innocuous as it triggers a transient but massive infiltration of Iba1+cells from the choroid to the retina that alters the retinal structure.

In the last decade, tissue engineering is a field that has been suffering an enormous expansion in the regenerative medicine and dentistry. The use of cells as mesenchymal dental stem cells of easy access for dentist and oral surgeon, immunosuppressive properties, high proliferation and capacity to differentiate into odontoblasts, cementoblasts, osteoblasts and other cells implicated in the teeth, suppose a good perspective of future in the clinical dentistry. However, is necessary advance in the known of growth factors and signalling molecules implicated in tooth development and regeneration of different structures of teeth. Furthermore, these cells need a fabulous scaffold that facility their integration, differentiation, matrix synthesis and promote multiple specific interactions between cells. In this review, we give a brief description of tooth development and anatomy, definition and classification of stem cells, with special attention of mesenchymal stem cells, commonly used in the cellular therapy for their trasdifferentiation ability, non ethical problems and acceptable results in preliminary clinical trials. In terms of tissue engineering, we provide an overview of different types of mesenchymal stem cells that have been isolated from teeth, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHEDs), periodontal ligament stem cells (PDLSCs), dental follicle progenitor stem cells (DFPCs), and stem cells from apical papilla (SCAPs), growth factors implicated in regeneration teeth and types of scaffolds for dental tissue regeneration. Key words:Dental stem cells, regenerative dentistry, mesenchymal stem cells, tissue engineering, stem cells.

The optimal post remission therapy for HR-ALL patients (pts) is not well established. This multicenter randomized trial was addressed to compare three options of post remission therapy in adults with HR-ALL: intensive consolidation plus maintenance chemotherapy (CHT), ALLO or AUTO SCT. Inclusion criteria: one or more of the following: age 30–50 yr., WBC&gt;25x109/L, t(9;22) or BCR/ABL, 11q23 or MLL and t(1;19). Treatment schedule: 5-drug (VCR, DNR, PDN, ASP, CPM) induction therapy over 5-weeks, followed by 3 1-wk cycles of early intensification CHT including HD-MTX, HD-ARAC and HD-ASP over 3 mo. Patients with an HLA-identical sibling were assigned to ALLO SCT and the remaining were randomized to AUTO SCT or to delayed intensification CHT (the same three cycles given in the post-remission period) followed by standard maintenance CHT (MP+MTX) up to 2-yr. in continuous complete remission (CR). Study period: 1993–2004, 254 pts included, 222 evaluable, 35 hospitals, 131 males, mean (SD) age 29(10) yr, WBC count 60(98) x109/L, early pre-B: 43 (19%), common+pre-B: 113 (51%), T: 66 (30%). Cytogenetics: 161 (73%) valid cases after central review, normal: 67 t(9;22): 37, 11q23: 6 cases, t(1;19): 2, other rearrangements: 49 cases. Response to therapy: CR 183 (82%). Slow response to therapy (&gt;10% blasts in BM aspirate at day 14 of induction therapy) in 40% of cases. 84 pts were assigned to ALLO SCT, 50 randomized to AUTO SCT and 48 to CHT, 1 pt. removed from protocol after the end of induction. With a median follow-up of 70 mo.(range 24–133), medians for DFS and OS for the whole series were 17 and 23 mo., and 5-yr DFS and OS probabilities were 35±5% and 34±6% (37±6% and 35±6% after removing Ph+ ALL pts from analysis). Groups of ALLO, AUTO and CHT were comparable for the main clinicobiologic characteristics and the rate of response to therapy. Intention-to-treat analysis showed no differences in DFS and in OS for donor vs. no donor comparison as well as for comparison of AUTO vs. CHT. This lack of differences persisted after removing Ph+ ALL pts from the analysis. The same results were observed when the analysis was performed on the basis of effectively treated pts (ALLO SCT performed in 70%, AUTO SCT in 62% and CHT in 73% of the pts). By multivariate analyses, age&gt;30 yr. was associated with death in induction, slow response to induction therapy and Ph+ ALL were associated with a lower CR, and these three variables had a negative influence on DFS and on OS probabilities. No differences in outcome were found in pts assigned to ALLO SCT or randomized to AUTO SCT or CHT as post-remission therapy in HR-ALL. DFS from ALLO or AUTO SCT or from intensification therapy was also identical in effectively treated patients. Adults with Ph+ ALL or slow response to induction therapy have been identified as a very-high-risk ALL subgroup for whom specific or experimental therapies are justified.