ALBERT

Description: Aneuploidy causes a proliferative disadvantage, mitotic and proteotoxic stress in non-malignant cells ( Torres et al. Science 2007). Chromosome gain or loss, which is the hallmark of aneuploidy, is a relatively common event in Acute Myeloid Leukemia (AML). About 10% of adult AML display isolated trisomy 8, 11, 13, 21 (Farag et al. IJO 2002), or either an isolated autosomal monosomy or monosomal karyotype (Breems et al. JCO 2008). This evidence suggests that tumor-specific mechanisms cooperate to overcome the unfitness barrier and maintain aneuploidy. However, the molecular bases of aneuploid AML are incompletely understood. We analyzed a cohort of 166 cytogenetically-characterized AML patients (80 aneuploid (A-) and 86 euploid (E-)) treated at Seràgnoli Institute (Bologna). Aneuploidy was significantly associated with poor overall survival (median survival: 13 and 26 months in A-AML and E-AML respectively; p=.006, Fig.1). To identify AML-specific alterations having a causative and/or tolerogenic role towards aneuploidy, we integrated high-throughput genomic and transcriptomic analyses. We performed 100 bp paired-end whole exome sequencing (WES, Illumina Hiseq2000) of 70 samples from our A-AML and E-AML cohort of 166 patients. Variants where called with MuTect or GATK for single nucleotide variant and indels detection, respectively. AML samples were genotyped by CytoScan HD Array (Affymetrix). Gene expression profiling (GEP) was also conducted on bone marrow cells from 24 A-AML, 33 E-AML (≥80% blasts) and 7 healthy controls (HTA 2.0, Affymetrix). We detected a significantly higher mutation load in A-AML compared with E-AML (median number of variants: 31 and 15, p=.04) which was interestingly unrelated to patients' age (median age: 63.5 years in A-AML and 62 years in E-AML, Xie et al, Nat. Med. 2014). C〉A and C〉T substitutions, which are likely mediated by endogenous 5mCdeamination, were the most frequent alterations (Alexandrov et al. Nat. 2013). However, aneuploidy associated with an increased variability in terms of mutational signatures, with the majority of A-AML displaying 3 or more signatures compared to few E-AML cases (p=.04). WES analysis also revealed a specific pattern of somatic mutations in A-AML. A-AML had a lower number of mutations in signaling genes (p=.04), while being enriched for alterations in cell cycle genes (p=.01) compared with E-AML. The mutated genes were involved in different cell cycle phases, including DNA replication (MCM6, PURB, SSRP1), centrosome dynamics (CEP250, SAC3D1, HEPACAM2, CCP110), chromosome segregation (NUSAP1, ESPL1, TRIOBP), mitotic checkpoint (ANAPC7, FAM64A) and regulation (CDK9, MELK, ZBTB17, FOXN3, PPM1D, USP2). Moreover, genomic deletion of cell cycle-related genes was frequently detected in A-AML. Notably, ESPL1 which associated with aneuploidy, chromosome instability and DNA damage in mammary tumors (Mukherjee et al. Oncogene 2014) was mutated and also upregulated in A-AML compared with E-AML (p=.01), the latter showing expression levels comparable to controls. Among the top-ranked genes differentially expressed between A-AML and E-AML, we identified a specific signature characterized by increased CDC20 and UBE2C and reduced RAD50 and ATR in A-AML (p

Description: Key Points UDS demonstrated that BCR-ABL KD mutations detectable with conventional methods may just be the tip of the iceberg. The information provided by conventional Sanger sequencing may not always be sufficient to predict responsiveness to a given TKI.

Description: Introduction. Autologous Bone Marrow Transplantation (Auto-BMT) is currently rarely used in the treatment of Acute Myeloid Leukemia (AML). However, it may represent a good therapeutic option in a specific subset of patients, mainly in consolidation of both low risk (LR) and MRD negative AML without an available HLA matched donor. Aims. To review our database of AML patients who received Auto-BMT from 2005 to 2014 and who were referred to Bologna Institution, in order to assess the efficacy of the procedure in terms of Overall Survival (OS) and Disease Free Survival (DFS). Patients and methods: From 2005 to 2014, 98 AML patients underwent Auto-BMT in several Italian Institutions. 89/98 patients are evaluable for survival and outcome data. The 89 patients considered (42 female, 47 male), had a median age of 49 years (range 15-70). Cytogenetics was performed in all patients by conventional karyotype (22 patients were also analyzed by Single Nucleotide Polymorphisms Array); molecular analysis (FLT3 TKD and ITD, and NPM1 mutational analysis) was available for 51/89 patients. Molecular monitoring by specific fusion transcripts (CBF-MYH11 and AML1-ETO) was performed in CBF positive leukemias (inv(16) and t(8;21)) at the time of diagnosis, after induction, consolidation courses, and every 3 months in the first 2 years of follow-up. Based on this data, and according to ELN guidelines, a risk stratification identified 41 patients with a LR AML (t(8:21), inv(16) or NPM1+/FLT3- with normal karyotype), 4 patients with a high risk (HR) AML (complex karyotype or FLT3 ITD mutated or inv(3) or t(6;9)) and 44 patients with a standard risk (SR) AML (normal karyotype, other alterations). Results. All the patients received an induction chemotherapy treatment, as follows: a "3+7-like" course in 48 cases, a Fludarabine-based regimen in 20 patients and a Gemtuzumab-ozogamicin (GO)-based regimen in 21. 83/89 (93.3%) patients received a median of 2 consolidation courses of chemotherapy (range 1-4) before proceeding to Auto-BMT, performed in 1st CR. 6/89 (6.7%) patients received Auto-BMT in first relapse. 41 patients relapsed after auto-BMT and were treated with a re-induction chemotherapy, or were enrolled in clinical trials. 24 patients reached a 2nd complete remission, and 12 patients underwent an allogeneic BMT in 2nd CR. With a median follow up of 6 years, the median Overall Survival (OS) of the entire population was 64.3 months (range 5.8-294.2 months); the 1 year OS and the 5 years OS were, 97.1%, and 67.9%, respectively. The median Disease Free Survival (DFS) of the 83 patients treated with Auto-BMT in 1st CR was 36 months (range 1.3-293 months). The 1-year DFS and the 5-years DFS were 85% and 56.7%, respectively. Transplant related mortality (TRM, death in 100 days after BMT) was 1.2% for auto-BMT and 6.5% for allogeneic BMT. First, to assess the role of the number of consolidation courses we compared patients who received none or 1 consolidation course with patients who received 2 or more cycles, who showed a better OS (p= 0.0061, Figure 1). There was no statistical difference in terms of OS between young and elderly patients (cut off=65 years). Second, we compared patients who achieved a negative minimal residual disease status before auto-BMT (n=37) with patients who did not (n=9). MRD negativity offered a significantly better outcome in terms of 5-years OS (83.4% and 50% respectively); the median OS of MRD neg was not yet reached; the median OS of MRD pos was 27 months (p= 0.0130) (Figure 2). Conclusions: Auto-BMT offers a chance to achieve long-term DFS and OS if used as a consolidation therapy both in patients with LR and SR AML. The major role could be played in MRD negative patients, offering the best chances to achieve a long-term OS. Auto-BMT can be also a good choice as consolidation therapy for elderly patients, in which allo-BMT could induce high morbidity and mortality rates. The small patients cohort and the retrospective analysis don't allow us to define the best induction therapy to be used before auto-BMT. However, based on our findings we suggest a therapy schedule including two or more consolidation courses in patients who obtain a first CR, and to proceed then to auto-BMT. Acknowledgments: work supported by ELN, AIL, AIRC, Progetto Regione-Università 2010-12 (L.Bolondi), Fondazione del Monte di Bologna e Ravenna, FP7 NGS-PTL project. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Soverini: Novartis, Briston-Myers Squibb, ARIAD: Consultancy. Rodeghiero:Celgene Corporation: Honoraria, Research Funding. Cavo:Janssen-Cilag, Celgene, Amgen, BMS: Honoraria. Martinelli:AMGEN: Consultancy; Novartis: Consultancy, Speakers Bureau; Ariad: Consultancy; BMS: Consultancy, Speakers Bureau; ROCHE: Consultancy; Pfizer: Consultancy; MSD: Consultancy.

Description: Systemic mastocytosis (SM) is a rare myeloproliferative neoplasm characterized by proliferation and hyperactivation of clonal mast cells. Clinical manifestations are heterogeneous and encompass cutaneous lesions, gastrointestinal alterations, osteoporosis, anaphylaxis and involvement of bone marrow and other organs due to neoplastic mast cells (MC) infiltration. As consequence, diagnosis may be difficult and patients (pts) are often evaluated by different specialists before the disease is recognized. To date, only few studies (Lim 2009, Escribano 2009, Cohen 2014) described relatively large series of pts with SM. We performed a multicentre retrospective study to evaluate clinical and biological features and therapeutic management in a large series of pts from 10 Italian centres experienced in management of SM and organized in multidisciplinary groups of specialists. We collected 455 pts diagnosed with SM according to WHO criteria. Additionally 26 pts with mastocytosis in the skin (MIS) evaluated with BM examination did not fulfil criteria for SM, leading to diagnosis of Cutaneous Mastocytosis (CM); however 2/26 pts with CM had both cKITD816V mutation and CD2/CD25 expression on MC in BM, additional 3 showed either cKITD816V or CD2/CD25. Moreover, we found 22 pts without MIS but with features of monoclonal mast cell activation syndrome. Of the 455 pts with WHO-SM (male 56%), 252 (55%) had MIS: median age at MIS diagnosis (dg) was 37 years (y) (range 0-79), while at SM dg it was 46.5 (range 18-82). Time from onset of MIS to dg of SM was 9 y (range 0-43). In 18/252 pts (7%) MIS occurred before age of 18 y (median 9, range 0-17) and persisted over childhood. Median age at dg of SM without MIS (203/455 pts, 45%) was older: 54 y, range 19-79 (p

Description: Abstract 2522 Introduction: Although p53 gene mutations are relatively infrequent in cases of B-ALL, the CDKN2A locus is deleted or inactivated in nearly half of all cases, especially Ph+ B-ALL (Mullighan et al., 2008; Iacobucci et al., 2011), contributing to a worse prognosis. In testing novel therapeutic approaches activating p53, we investigated the preclinical activity of the MDM2 antagonist Nutlin-3a in leukemic cell line models and primary B-ALL patient samples. Methods: TP53 mutation screening was performed by Sanger sequencing of exons 4 to 11; copy number status of CDKN2A was determined by MLPA kit P335-A2 ALL-IKZF1 (MRC Holland); cellular viability was assessed by using a colorimetric assay based on mitochondrial dehydrogenase cleavage of WST-1 reagent (Roche); apoptosis was assessed by use of Annexin V/Propidium Iodide (PI); gene expression profile was performed using Affymetrix GeneChip Human Gene 1.0 ST platform (Affymetrix). Mdm2 inhibitor (Mdm2i) Nutlin-3a was provided by Roche. Results: BCR-ABL1-positive (BV-173, SUPB-15) and negative (NALM19, REH) ALL cell lines were investigated for TP53 mutations and CDKN2A deletion. A p53 mutation (R181C) was identified in REH cells, whereas all the remaining cell lines resulted p53 wild-type but they were deleted in the locus containing CDKN2A. Leukemia cell lines were incubated with increasing concentrations of Nutlin-3a (0.005–2 μM) for 24, 48 and 72 hours (hrs). Mdm2 inhibition resulted in a dose and time-dependent cytotoxicity with IC50 at 24 hrs ranging from around 1.5 μM for BV-173 and SUPB-15 to 3.7 μM for NALM-19. By contrast, no significant changes in cell viability were observed in RHE p53-mutated cells after incubation with Mdm2i. The time and dose-dependent reduction in cell viability were confirmed in primary blast cells from a Ph+ ALL patient with the T315I Bcr-Abl kinase domain mutation found to be insensitive to the available tyrosine kinase inhibitors and from a t(4;11)-positive ALL patient (IC50 at 24 hrs equal to 2 μM). Consistent with the results of cell viability, Annexin V/PI analysis showed a significant increase in apoptosis after 24 hrs in sensitive cell lines and in primary leukemia blasts, whereas no apoptosis was observed in REH cells. To examine the possible mechanisms underlying Mdm2i-mediated cell death, western blot analysis was performed. Protein levels of p53, p21 (an important mediator of p53-dependent cell cycle arrest), cleaved caspase-3 and caspase-9 proteins increased as soon as 24 hrs of incubation with Mdm2i. In order to better elucidate the implications of p53 activation and to identify biomarkers of clinical activity, gene expression profiling analysis was next performed, comparing sensitive cell lines at 24 hrs of incubation with concentrations equal to the IC50 and their untreated counterparts (DMSO 0.1%). A total of 621 genes (48% down-regulated vs 52% up-regulated) were differentially expressed (p 〈 0.05). We found a strong down-regulation of GAS41 (growth-arrest specific 1 gene) and BMI1 (a polycomb ring-finger oncogene) (fold-change −1.35 and −1.11, respectively; p-value 0.02 and 0.03, respectively) after in vitro treatment as compared to control cells. Both genes are repressors of INK4/ARF and p21 and their aberrant expression has found to contribute to stem cell state in tumor cells. Additionally, experimental reduction of BMI1 protein levels results in apoptosis in tumor cells and increases susceptibility to cytotoxic agents and radiation therapy (Wu et al., 2011). Given the importance of BMI in the control of apoptosis, we investigated by western blot its pattern in treated and untreated cells, confirming a marked decrease as soon as 24 hrs of exposure to MDM2i both in leukemia cell lines and primary blast samples. Noteworthy, the BMI-1 levels remained constant in resistant cells. Conclusions: Inhibition of Mdm2 efficiently activates the p53 pathway promoting apoptosis. BMI-1 expression is markedly reduced in sensitive cells and it may be used as a biomarker of response. Evaluation of its expression before and after treatment in clinical settings will better gain insight into its role. Supported by: ELN, AIL, AIRC, Fondazione Del Monte di Bologna e Ravenna, Ateneo RFO grants, Project of integrated program, Programma di Ricerca Regione – Università 2007 – 2009, INPDAP. Disclosures: Soverini: Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; ARIAD: Consultancy. Baccarani:ARIAD, Novartis, Bristol Myers-Squibb, and Pfizer: Consultancy, Honoraria, Speakers Bureau. Martinelli:BMS: Consultancy, Honoraria, Speakers Bureau; NOVARTIS: Consultancy, Honoraria, Speakers Bureau; PFIZER: Consultancy; ARIAD: Consultancy.

Description: Rationale: Inotuzumab ozagomicin (IO) has been linked to an increased incidence of veno-occlusive disease (VOD) and liver alterations. Most VOD events occurred during hematopoietic stem cell (HSCT) transplantation after IO therapy. We have previously described that the measurement of liver stiffness can anticipate the diagnosis of VOD in the context of HSCT. The mechanisms underlying the increased risk of VOD and liver damage in patients receiving IO are not well understood; in the pathogenesis endothelial damage, ozagomicin release and on-target off-tumor effects may be involved. Here, we aimed to assess the effects of IO on the changes of liver, vascular and biochemistry parameters. Methods: Intensive monitoring of the liver was incorporated into the standard of care of patients who received IO for relapsed or refractory (R / R) acute lymphoblastic leukemia (ALL). Upper abdomen ultrasound with Doppler was performed at baseline and at the end of therapy; liver stiffness measurement (LSM) by Fibroscan® (Echosens, Paris, France) at every IO course or at every IO infusion. With the exception of ursodeoxycholic acid, the patients did not receive prophylaxis for VOD. Data was collected after anonymous aggregation, in accordance with GCP and Helsinki declaration. Results are reported as median with interquartile ranges (IQR). Results: At data cut-off, 1st Apr 2019, 16 patient received baseline assessment and at least a post-IO assessment in our monitoring program. In our patent set, median age was 44.5 (IQR 30.7 - 64.0); 12/16 (75 %) patients relapsed after the last treatment and 4/16 (25 %) patients were refractory to the last treatment; patients received a median of 3 (IQR 2 - 3.7) lines before IO; 6/16 (37.5 %) patients undergone HSCT before IO, of which a patient had 1st and 2nd HSCT before IO; 5/16 (31.25 %) undergone HSCT after IO therapy (no patients had second HSCT after IO). Patients received a median of 2 (IQR 2.0 - 3.7) IO administration according to the schedule of the phase 3 trial. The median duration of the therapy was 61.5 days (IQR 43.2 - 114.0) and median progression-free survival in our population was 278.0 days (95% C.I. 264.0 - 292.0). In our patient set, we performed 113 biochemistry determination, 30 liver ultrasounds with Doppler and 116 LSM examination. One patient received a liver biopsy. Among the biochemical exams (AST, ALT, GGT and alkaline phosphatase) only the AST values significantly increased after 1st course of IO (from the median value of 21 U/L to 53 U/L after course 3). Liver ultrasound with Doppler revealed portal hypertension signs in half of the patients during IO monitoring program. Among these patients 7/16 (44%), 3/16 (17%), 5/16 (33.3%) and 3/16 (17%) showed splenomegaly, recanalization of the paraumbilical vein, dilatation of portal vein and ascites, respectively. Median LSM significantly increased from a baseline value of 6 kPa to 7.8 kPa after last post-IO assessment (p-value 7.1 kPa). With a median follow up of 387.5 days (IQR 182.8-524.5) we observed one VOD event (7%); the VOD was graded severe and occurred after HSCT post-IO. Conclusions: Our clinical experience represents the first step to better understand the IO-related liver alterations, as we described the frequency and relevance of quantitative markers. Most of the patients in our set developed ultrasound and/or elastography alteration during IO therapy. Furthermore, these alterations do not seem to correlate with biochemistry. Even if most of the patients had sub-clinical vascular and parenchymal alterations of the liver portal-hypertension related, VOD incidence in our set is comparable with literature. Long-term follow-up results are expected to test whether alterations return or evolve over time. Stratifying the tailored risk liver complications with prospective non-invasive and marker-driven strategies in term of IO dosing and HSCT timing could be a great benefit for patients. * FR and GM contributed to this manuscript equally # AC and CP contributed to this manuscript equally Figure Disclosures Martinelli: Roche: Consultancy; BMS: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; ARIAD: Consultancy. Cavo:janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; novartis: Honoraria; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau. Papayannidis:Amgen: Honoraria; Novartis: Honoraria; Teva: Honoraria; Pfizer: Honoraria; Incyte: Honoraria; Shire: Honoraria.

Description: Abstract 3136 Deletions of the 9p21 chromosomal region are frequent events for the development of a variety of cancers, including solid tumors and hematological malignancies, such as childhood ALL. This region contains the 40-kb region encoding the p16INK4a/CDKN2A (cyclin-dependent kinase inhibitor 2a) tumor suppressor gene and two other related genes, p14/ARF and p15INK4b/CDKN2B, all of which encode critical factors for the regulation of cell cycle and/or apoptosis. In order to explore the frequency and size of deletions affecting the 9p21 locus in adult BCR-ABL1-positive ALL, to determine the main mechanism of inactivation and to investigate the influence on the prognosis, 112 patients were analyzed: 82 (73%) de novo cases, 11 (10%) unpaired relapse cases, 19 (17%) diagnosis-relapse matched samples. The median age was 53 years (range: 18–76) and the median blast percentage was 90% (range, 18–99). Affymetrix single nucleotide polymorphism (SNP) arrays (GeneChip® Human Mapping 250K NspI and Genome-Wide Human SNP 6.0) were used to identify at a high resolution copy number changes on 9p21. PCR amplification and mutation screening of each exon by cloning and subsequent sequencing were also performed. Moreover, gene-expression profiling was performed (Affymetrix Human Exon 1ST Array) to draw a specific signature associated with deletions. At diagnosis, CDKN2A/ARF and CDKN2B genomic alterations were identified in 29% and 24% of patients, respectively. Deletions were monoallelic in the majority of cases (72%) with a median of 1,012 kb in size (range, 2.8–31,319 kb). In some of them, 43%, the minimal overlapping region of the lost area spanned only the CDKN2A/ARF/CDKN2B gene locus, but more often (57%) the loss was considerable larger and extended sometimes over the entire short arm eliminating a large number of genes. In contrast, cases with bi-allelic inactivation were 28% with the majority of deletions (75%) limited to CDKN2A/ARF/CDKN2B genes. FISH analysis was performed using three different BAC clones, but since they overlooked microdeletions we only appreciated a mild fluorescent signal reduction. In order to assess whether 9p21 loss is responsible for progression, the genomic status of this locus was assessed at the time of relapse and an almost significant increase in the detection rate of CDKN2A/ARF loss (47%) compared to diagnosis (p = 0.06) was found. Functionally, deletions led to a strong down-regulation at the transcript level of CDKN2A/ARF (p= 0.0005), as demonstrated by Fluidigm Dynamic Array real-time qPCR assay (Fluidigm Corporation, South San Francisco, CA) which enables to perform TaqMan nano-reactions at high sensitivity. Finally, the mutation screening performed on each exon of ARF, CDKN2A and CDKN2B genes showed that the 9p21 locus is rarely affected by point mutations with only the identification of the missense D146N in the CDKN2A exon 2. Furthermore, 2 mutations were found in the 5′UTR of CDKN2A [UTR A 21965011 (33%), UTR G/A 21965011 (47%), UTR C/T 21964875 (3%)] and a variation, known as SNP was found in the exon 2 (rs3731249). Finally, 2 SNPs were found in the 3′ UTR region of CDKN2A/ARF (rs11515 and rs3088440). The role of the mutations identified in the UTR is not yet defined, but the comparison with the germline material from saliva samples showed that these mutations were inherited. Since the prognostic relevance of CDKN2A/ARF deletions is still controversial in literature, we addressed this issue in our study cohort, finding out that deletions in this locus are significantly associated with poor outcome both in terms of disease free-survival (p=0.003) and cumulative incidence of relapse (p= 0.004). In conclusion, the inactivation of the tumor suppressor genes CDKN2A/ARF is a frequent event in Ph+ ALL. The main mechanism of inactivation is represented by genomic deletions, whereas missense mutations are rare. Deletions are frequently acquired at the leukemia progression and work as a poor prognostic marker, impairing disease free-survival and cumulative incidence of relapse. Novel treatment strategies targeting the ARF-MDM2-p53 pathway may be effective in this subset of patients and in vitro studies are ongoing to confirm this hypothesis. Supported by: European LeukemiaNet, AIL, AIRC, Fondazione Del Monte di Bologna e Ravenna, FIRB 2006, Ateneo RFO grants, Project of integreted program (PIO), Programma di Ricerca Regione – Università 2007 – 2009. Disclosures: Baccarani: Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Martinelli:Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Pfizer: Consultancy.

Description: The BCR-ABL1 fusion gene defines the subgroup of acute lymphoblastic leukemia (ALL) with the worst clinical prognosis. To identify oncogenic lesions that combine with BCR-ABL1 to cause ALL, we used Affymetrix Genome-Wide Human SNP arrays (250K NspI and SNP 6.0), fluorescence in situ hybridization, and genomic polymerase chain reaction to study 106 cases of adult BCR-ABL1–positive ALL. The most frequent somatic copy number alteration was a focal deletion on 7p12 of IKZF1, which encodes the transcription factor Ikaros and was identified in 80 (75%) of 106 patients. Different patterns of deletions occurred, but the most frequent were those characterized by a loss of exons 4 through 7 (Δ4-7) and by removal of exons 2 through 7 (Δ2-7). A variable number of nucleotides (patient specific) were inserted at the conjunction and maintained with fidelity at the time of relapse. The extent of the Δ4-7 deletion correlated with the expression of a dominant-negative isoform with cytoplasmic localization and oncogenic activity, whereas the Δ2-7 deletion resulted in a transcript lacking the translation start site. The IKZF1 deletion also was identified in the progression of chronic myeloid leukemia to lymphoid blast crisis (66%) but never in myeloid blast crisis or chronic-phase chronic myeloid leukemia or in patients with acute myeloid leukemia. Known DNA sequences and structural features were mapped along the breakpoint cluster regions, including heptamer recombination signal sequences recognized by RAG enzymes during V(D)J recombination, suggesting that IKZF1 deletions could arise from aberrant RAG-mediated recombination.

Description: Background: AML is a heterogeneous disease with various chromosomal aberrations. The karyotype at diagnosis provides important prognostic information that influences therapy and outcome, and patients (pts) with complex karyotype (CK) have generally a poor outcome. TP53 is the most frequently mutated gene in human tumors. The reported TP53 mutation rate in AML is low (2.1%). In contrast, the incidence of TP53 mutations in AML with a complex aberrant karyotype is higher (69-78%). Aims: To investigate the frequency, the types of mutations, the associated cytogenetic abnormalities and the prognostic role of TP53 mutations in adult AML pts, we focused the screening on subgroups of AML with chromosome abnormalities. Patients and Methods: 886 AML patients were analysed at the Seràgnoli Institute of Bologna between 2002 and 2013 for morphology, immunophenotype, cytogenetic and for a panel of genetic alterations (FLT3, NPM, WT1, CBF fusion transcripts, DNMT3A, IDH1, IDH2, etc). Of these, 172 adult AML pts were also examined for TP53 mutations using several methods, including Sanger sequencing, Next-Generation deep-Sequencing (Roche) and HiSeq 2000 (Illumina) platform (35/172 pts). 40 samples were genotyped with Genome-Wide Human SNP 6.0 arrays or with CytoScan HD Array (Affymetrix) and analysed by Nexus Copy Number™ v7.5 (BioDiscovery). Results: Of the 886 AML patients beforehand analysed, 172 pts were screened for TP53 mutations and were correlated with cytogenetic analysis (excluding 15 pts where the karyotype was not available). 1. Fifty-two pts (30,2%) have 3 or more chromosome abnormalities, i.e. complex karyotype; 2. 71 (41,3%) presented one or two cytogenetic abnormalities (other-AML) and 3. 34 pts (19,8%) have normal karyotype. Sanger sequencing analysis detected TP53 mutations on 29 patients with 36 different types of mutations; seven pts (4%) have 2 mutations. Mostly (23/29) of the TP53 mutated pts (79.3%) had complex karyotype while only 6/29 mutated pts have “no CK” (21% and 3% of the entire screened population). Overall, between pts with complex karyotype, TP53 frequency is 44.2%. Regarding the types of the TP53 alterations, 32 were deleterious point mutations (http://p53.iarc.fr/TP53GeneVariations.aspx) and 4 deletions. Forty pts were also analysed for Copy Number Alterations (CNAs) by Affymetrix SNP arrays: several CNAs were found ranged from loss or gain of complete chromosome (chr) arms to focal deletions and gains targeting one or few genes involving macroscopic (〉1.5 Mbps), submicroscopic genomic intervals (50 Kbps - 1.5 Mbps) and LOH (〉5 Mbps) events. Of relevance, gains located on chr 8 were statistically associated with TP53 mutations (p = 0.001). Seven genes are included in these regions (RGS20, TCEA1, LINC01299, ARMC1, MTFR1, RAD54B, KIAA1429). In addition to the trisomy of the chr 8, others CNAs, located on other chromosomes are significantly associated (p = 0.05) with TP53 mutations: loss of chr 5q, chr 3 (p22.3), chr 12 (p12.3) and the gain of chr 17 (p11.2), chr 16 (p11.2-11.3) and chr 14 (q32.33). The zinc finger gene ZNF705B, implicated in the regulation of transcription was the most differentially associated gene (gain). WES analysis was done in 37 pts, 32 TP53 were wt while 5 pts were TP53 mutated: of importance, CDC27, PLIN4 and MUC4 were found also mutated in 3 out of 5 TP53 mutated (60%). Clinical outcome: as previously reported, alterations of TP53 were significantly associated with poor outcome in terms of both overall survival and disease free-survival (P 〈 0.0001). Conclusions: Our data demonstrated that TP53 mutations occur in 16.86% of AML with a higher frequency in the subgroup of complex karyotype AML (p〈 0.0001–Fischer’s exact test). Since TP53 mutations have predicted to be deleterious and significantly correlated with prognosis, TP53 mutation screening should be recommended at least in complex karyotype AML pts. Furthermore, although further studies in larger numbers of patients are needed, the gain of chromosome 8 was observed to be significantly associated to TP53 mutations pts. Supported by: ELN, AIL, AIRC, PRIN, progetto Regione-Università 2010-12 (L. Bolondi), FP7 NGS-PTL project. Disclosures Martinelli: Novartis: Speakers Bureau; Bristol Mayers Squibb: Speakers Bureau; Pfizer: Speakers Bureau.

Description: Human systemic mastocytosis (SM) is a rare disease caused by an abnormal mast cells accumulation in various tissues. It usually occurs as a sporadic disease that is often persistent or progressive in adults. Clinical course is variable. The most aggressive forms have a rapid course and required treatments to reduce the neoplastic burden and to slacken the progression. Unfortunately no therapy have been demonstrated efficacy, mostly in the treatment of aggressive systemic mastocytosis (ASM). SM has been associated with constitutive activating c-kit somatic mutations, the most frequent of whom is the D816V mutation. Kinase inhibitors blocking constitutive c-kit activation, such as imatinib, have been used in SM, but they had no effect on D816V mutant kit. Here, we report on six patients with Systemic mastocytosis and with detectable D816V mutation treated with dasatinib 70 mg BID as in leukemia treatment. According to the WHO Classification of Systemic mastocytosis, we describe clinical characteristics of six cases of ASM with different organ damage treated with dasatinib for various period, and we made evaluation of response according to Valent criteria (Leuk Research, 2003). All patients excepting Patient 3 reached the dose of 140 mg daily. Patient 4 are on treatment after 10 months, without any signs or symptoms of disease progression. Patient 2 is still on treatment with low dose of dasatinib (20 mg daily) but he shows cytopenia and worsening clinical condition, he does not tolerate high dose of dasatinib for gastrointestinal toxicity and astenia. Patient 1 stopped therapy after 10 months of therapy and she relapsed with ascite and died after 1 month for progressive disease. Patient 3 and Patient 5 interrupted dasatinib for worsening clinical condition after 40 days and three months respectively. Patient 6 stopped dasatinib after five months for progression to acute leukemia. After dasatinib suspension, Patient 3 died for complication of leg fracture and Patient 5 died for progression of disease. We observed major response in three patients for the prompt resolution of sign of organ damage recorded during dasatinib treatment, and we also obteined a measurable decrease of the burden of neoplastic MCs by means of tryptase level monitoring in all but one patients. Toxicity of 140 mg daily in patients with advanced ASM is notable. All patients had to suspended therapy due to extra-haematological toxicity. The most commonly toxicity involved gastroenteric tract, with diarrohea and abdominal pain, hypotension and pleural effusion. Symptoms resolved or return to mild grade with dose reduction, but in frail patients therapy is not well tolerate. After interruption of therapy progression was recorded.