The enormous plasticity of mesenchymal stem cells (MSCs) suggests an improvement of a standard protocol of isolation and ex vivo expansion for experimental and clinical use. We isolated and expanded MSCs from bone marrow (BM) of pediatric and young adult donors, to analyze the growth kinetic, immunophenotype, telomere length, karyotype during ex vivo expansion. Seventeen BM samples were collected from young adult donors and 8 from pediatric donors. MSCs isolated from two groups showed no morphological differences while their cell growth was strictly related to the donor's age. The MSCs isolated from pediatric donors reached a cumulative PD almost twice as high as MSCs isolated from young adult donors after 112 days (10.2 +/- 1.9 versus 5.5 +/- 3.7). Furthermore, we analyzed the modulation of antigen expression in the MSCs isolated from two groups until 10th passage (77 days) and there was no significant difference between the modulation of antigen expression. In particular, at the first passage, MSCs showed a low contamination of hemopoietic cells which became insignificant in the following passages. There was a high expression of CD90, CD29, CD44 and CD105 and variable and moderate expression of CD166 and CD106 at the start of MSC culture and at each passage during expansion. No chromosomal alteration or evidence of cellular senescence were observed in all analyzed samples. All these data suggest that MSCs can be isolated and expanded from most healthy donors, providing for an autologous source of stem cells.

Angiogenesis is considered a hallmark of multiple myeloma (MM) progression. In the present study, we evaluated the morphological and functional features of endothelial cells (ECs) derived from bone marrow (BM) of patients affected by MM (MMECs). We found that MMECs compared with normal BM ECs (BMECs) showed increased expression of syndecan-1. Silencing of syndecan-1 expression by RNA interference technique decreased in vitro EC survival, proliferation and organization in capillary-like structures. In vivo, in severe combined immunodeficient mice, syndecan-1 silencing inhibited MMEC organization into patent vessels. When overexpressed in human umbilical vein ECs and BMECs, syndecan-1 induced in vitro and in vivo angiogenic effects. Flow-cytometric analysis of MMECs silenced for syndecan-1 expression indicated a decreased membrane expression of vascular endothelial growth factor (VEGF) receptor-2 (VEGFR-2). Immunoprecipitation and confocal analysis showed colocalization of VEGFR-2 with syndecan-1. Absence of nuclear translocation of VEGFR-2 in syndecan-1-knockdown cells together with the shift from perinuclear localization to recycling compartments suggest a role of syndecan-1 in modulation of VEGFR-2 localization. This correlated with an in vitro decreased VEGF-induced invasion and motility. These results suggest that syndecan-1 may contribute to the highly angiogenic phenotype of MMECs by promoting EC proliferation, survival and modulating VEGF–VEGFR-2 signalling.

SummaryAbnormal activation of MET/HGF (Hepatocyte Growth Factor) pathway has been described in several tumours and increased HGF plasmatic levels have been detected in patients with aggressive multiple myeloma (MM). MET and HGF mRNA expression was investigated in 105 samples of purified plasma cells derived from newly diagnosed MM patients treated with bortezomib-based induction therapy. Gene expression was compared with response to therapy and clinical outcome. MET gene copy number was also evaluated. MET mRNA expression was higher in CD138 + than in CD138 À cells (median 76Á90 vs. 11Á24; P = 0Á0009). Low MET mRNA expression characterized patients with better response (complete response or very good partial response) compared to other patients (median 56Á10 vs. 134Á83; P = 0Á0006). After a median follow-up of 50 months, patients with high MET mRNA expression displayed a worse progression-free survival (PFS; P = 0Á0029) and overall survival (OS; P = 0Á0023) compared to those with low MET mRNA levels. Patients with both high MET mRNA expression and high b2-microglobulin level (>5Á5 mg/l) had further worse median PFS (P < 0Á0001) and OS (P < 0Á0001). Patients carrying 4 MET gene copies (8 out of 82, 9Á8%) also had a short PFS. High MET mRNA expression identifies patients with dismal PFS and OS and the combination with high b2-microglobulin further characterizes patients with worse outcome.

ABSTRACT(<10%) and is considered an adverse prognostic factor in young patients. 15,16 The relevance of chromosome 1 (chr1) abnormalities has been reported in several studies: Shaughnessy et al. defined a 70-gene high-risk signature, in which 30% of genes mapped to chr1, suggesting the significant poor prognostic impact of gain(1q) and del(1p). 17

Background High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) improves survival in multiple myeloma (MM). The introduction of novel agents challenged the role of ASCT at diagnosis. We conducted a multicenter 2X2 randomized trial comparing conventional chemotherapy plus lenalidomide with ASCT followed by maintenance with lenalidomide-prednisone (RP) or lenalidomide (R) alone in newly diagnosed young MM (NDMM) patients. Methods Eligible patients with NDMM ≤ 65 years were enrolled. All patients received Rd induction (four 28-day cycles of lenalidomide 25 mg day 1–21 and low-dose dexamethasone 40 mg day 1,8,15,22) followed by stem cell mobilization. Patients were randomized to receive consolidation with CRD [six 28-day cycles of cyclophosphamide (300 mg/m2 day 1,8,15), dexamethasone (40 mg days 1,8,15,22) and lenalidomide (25 mg days 1–21)] or MEL200-ASCT (melphalan 200 mg/m2 with stem-cell support). Patients were randomly assigned to receive subsequent maintenance with RP (28-day cycles of lenalidomide 25 mg days 1–21 plus prednisone 50 mg every other day) or R alone (28-day cycles of lenalidomide 25 mg days 1–21). Primary study endpoint was progression-free survival (PFS); secondary endpoints included safety, responses and overall survival (OS). Data cut off was May 30th, 2013. Results Three-hundred and eighty-nine patients were enrolled in the trial. Patient characteristics were well balanced between CRD (n=194) and MEL200-ASCT (n=195), and between R (n=195) and RP (n=194) arms. Median follow-up was 31 months. In the intent to treat (ITT) analysis, the median PFS was not reached with MEL200-ASCT and 28 months with CRD (the respective 3-year PFS was 60% vs. 38%, HR=0.62, 95%CI: 0.49-0.85, P=0.003). Median time from enrolment to maintenance was 14 months. In the population of patients eligible for maintenance, 2-year PFS from the start of maintenance was 73% for RP and 56% for R patients (HR= 0.57, 95%CI: 0.34-0.93; P=0.03). In the subgroup of patients who received MEL200-ASCT, 2-year PFS from the start of maintenance was 83% for patients who received RP and 64% for those who received R alone (HR=0.36 95%CI: 0.15-0.87, P=0.02). In the subgroup of patients who received CRD, 2-year PFS from the start of maintenance was 64% for patients who received RP and 47% for those who received R alone (HR=0.75, 95%CI: 0.40-1.39, P=0.36). At present, no differences in OS were noticed between patients randomised to received CRD or MEL200-ASCT, and between patients who received RP or R maintenance. As expected, the rates of grade 3-4 hematologic (85% vs. 26%, P<0.001) and non-hematologic (35% vs. 19%, P=0.003) adverse events (AEs) were higher in the MEL200-ASCT arm compared with the CRD arm. The main non-hematologic AEs were infections (18% vs. 5%, P=0.001) and gastrointestinal AEs (18% vs. 3%, P<0.001). Rates of grade 3-4 hematologic (8% vs. 7%, P=0.85) and non-hematologic (12% vs. 13%, P=0.88). AEs were similar in the RP and R arms. The main non-hematologic AEs in both RP and R groups were infections (3% vs. 3%). At present, 6 second primary malignancies and 3 cases of cutaneous basalioma have been reported. Conclusions MEL200-ASCT significantly prolonged PFS in comparison with CRD. At present no difference in OS was reported, this may be due to the low number of events and to the length of follow-up. The increase in toxicity with MEL200-ASCT did not adversely impact on efficacy. The addition of prednisone to lenalidomide maintenance significantly reduced the risk of progression in comparison with lenalidomide alone, without increasing the toxicity. Updated data with longer follow-up will be presented at the meeting. Disclosures: Palumbo: Amgen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen Pharmaceuticals: Consultancy, Honoraria; Millenium: Consultancy, Honoraria; Onyx: Consultancy, Honoraria. Gay:Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Spencer:Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Larocca:Celgene: Honoraria. Caravita:Celgene: Honoraria, Research Funding. Petrucci:Celgene: Honoraria. Hajek:Celgene: Honoraria; Celgene: Consultancy. Boccadoro:Celgene: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Research Funding.

Background Carfilzomib is a novel second generation proteasome-inhibitor with significant anti-MM activity and favorable toxicity profile. In a recent phase 1/2 study in relapsed/refractory patients (pts) a weekly schedule of carfilzomib in combination with dexamethasone showed to be effective (overall response rate of 77%) and safe (ASCO 2015). The ongoing phase 3 ARROW study is comparing once- with twice-weekly carfilzomib. In the newly diagnosed setting, no data are available on weekly carfilzomib. We designed a phase 1/2 study of weekly carfilzomib in combination with cyclophosphamide and dexamethasone (wCCyd) for newly diagnosed MM pts. Results of the dose-escalation phase 1 portion of study were previously reported (Palumbo A et al, Blood 2014), the maximum tolerated dose of weekly carfilzomib was established as 70 mg/m2. Here we report efficacy and safety results of the phase 2 portion of the study. Methods Newly diagnosed pts ineligible for autologous stem-cell transplantation due to age or co-morbidities were enrolled in the phase 2 portion of the study. Pts received IV carfilzomib at the maximum tolerated dose 70 mg/m2 on days 1, 8, 15 combined with oral cyclophosphamide at 300 mg/m2 on days 1, 8, 15 and oral dexamethasone at 40 mg on days 1, 8, 15, 22, in 28-daycycles. After the completionof 9 cycles, pts received 28-day maintenance cycles with carfilzomib at 70 mg/m2 on days 1, 8, 15 until disease progression or intolerance. The primary objectives were to determine the efficacy and safety of wCCyd. The secondary objectives included the evaluation of time to progression, progression-free survival, time to next therapy and overall survival. Response was assessed according to the modified International Uniform Response Criteria. Adverse events (AEs) were graded following NCI-CTCAE v4. Results As of July 15, 2015, 47 newly diagnosed MM pts were enrolled in the phase 2 portion of the study. Median age was 72 years, 23% of pts were older than 75 years, 30% had ISS stage III, 34% had unfavorable FISH profile [t(4;14) or t (14;16) or del17p or amp1]. Toxicityand response data were available in 40 pts, who completed atleast the first cycle; 7 pts were still receiving their first cycle of treatment. Pts received a median of 6 cycles (range 1-9). Overall, 80% of pts achieved at least a partial response, 60% at least a very good partial response, and 28% a near complete response. Responses improved over time (Table 1). During the study, 9 pts progressed or died, the progression-free survival at 1 year was 75%. Grade (G) 3-4 drug-related adverse events included neutropenia (22%, 9 pts), thrombocytopenia (7%, 3 pts), infection (10%, 4 pts), acute pulmonary edema (5%, 2 pts), creatinine increase (5%, 2 pts), fever (2.5%, 1 pt), fatigue (2.5%, 1 pt) and headache (2.5%, 1 pt). G1-2 hypertension was reported in 6 pts (15%). No peripheral neuropathy was reported. Overall, the wCCyd regimen was well tolerated, 4 pts (10%) required carfilzomib dose-reduction (G3 hematologic toxicities [2 pts], G3 headache [1 pt] and G2 fatigue [1 pt]) and 9 pts (22%) required treatment discontinuation due to adverse events (2 infections, 1 acute pulmonary edema, 1 creatinine increase, 1 fever, 1 pt condition, 1 second tumor, 1 pericardial effusion, 1 sudden death). Conclusions This is the first prospective study evaluating once-weekly carfilzomib in treatment-naïve MM. wCCyd therapy appears safe and effective in newly diagnosed MM pts. Responses became deeper with subsequent cycles and toxicities were manageable. The response rate observed with weekly carfilzomib compares favorably with similar studies with standard twice-weekly carfilzomib infusion. Updated results will be presented at the meeting. Table 1. 2nd cycle 6th cycle 9th cycle Complete Response 17% 26% 33% At least near Complete Response 29% 39% 40% At least Very Good Partial Response 66% 82% 87% At least Partial Response 86% 87% 87% Disclosures Bringhen: Janssen-Cilag, Celgene, Novartis: Honoraria; Onyx: Consultancy; Merck Sharp & Dohme: Membership on an entity's Board of Directors or advisory committees. Off Label Use: Use off-label of drugs for the dose and/or schedule and/or association. Larocca:Janssen-Cilag, Celgene: Honoraria. Offidani:Janssen-Cilag, Celgene, Sanofi, Amgen, Mundipharma: Honoraria. Gaidano:Celgene, Onyx: Membership on an entity's Board of Directors or advisory committees. Boccadoro:Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Onyx Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees. Sonneveld:Janssen-Cilag, Celgene, Onyx, Karyopharm: Honoraria, Research Funding; novartis: Honoraria. Palumbo:Celgene, Millennium Pharmaceuticals, Amgen, Bristol-Myers Squibb, Genmab, Janssen-Cilag, Onyx Pharmaceuticals: Consultancy, Honoraria; Novartis, Sanofi Aventis: Honoraria.

Ependymomas are glial tumours representing approximately 5-10% of all intracranial tumours and are the third most common primary brain tumour in childhood. Only a few karyotypic studies on paediatric ependymomas have been published and no specific chromosomal aberration has been specifically related to this type of cancer. We performed cytogenetic analysis of an ependymoma in an 11-year-old boy. Our patient showed a complex karyotype, characterized by a near-tetraploidy and a sole structural unbalanced aberration: der(2)t(2;11)(q11.2;q13.1), which has not been described before. We here discuss such cytogenetic findings, comparing our data with those reported in the literature.

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