ALBERT

Description: Abstract 4785 Background The karyotype is an important predictor of outcome in adults with acute lymphoblastic leukemia (ALL). Some groups have reported the negative prognostic value of complex karyotype (CK, defined as ≥5 unrelated chromosomal abnormalities) in adult ALL (Moorman et al, Blood. 2007:109;3189-97). On the other hand, monosomal karyotype (MK, defined as ≥2 distinct autosomal chromosome monosomies or 1 single monosomy in the presence of structural abnormalities) has been associated with a worse outcome in patients with acute myeloid leukemia. We aimed to assess the prognostic value of cytogenetic abnormalities, especially CK and MK, in adults with ALL treated with protocols of the Spanish PETHEMA Group. Patients and Methods The karyotypes of 783 adult ALL patients from 63 Spanish centers treated according to the protocols of the PETHEMA Group between 1993 and 2011 were reviewed. The several PETHEMA protocols were risk-adapted (standard-risk –SR–, high-risk –HR–) or subtype-oriented (Philadelphia chromosome [Ph+] ALL -with or without imatinib-, and Burkitt's ALL [BL]). The impact of the main cytogenetic abnormalities as well as of the CK and MK on complete remission (CR) rate, CR duration, overall survival (OS) and event-free survival (EFS) was analyzed. Results The median age of the series was 33 years (range 15–82) and 448 patients (57.2%) were male. The karyotypes of 560 out of 783 patients were evaluable after review: normal karyotype 153 patients, t(9;22) 120, t(v;11q23) 30, t(8;14), t(8;22) or t(2;8) 47, high hyperdiploidy (〉50 chromosomes) 53, low hyperdiploidy (47–50 chromosomes) 52, hypodiploidy (45–39 chromosomes) 32 and extreme hypodiploidy (

Description: Abstract 4725 In the last twenty years enzyme replacement therapy (ERT) with imiglucerase has been a clinically effective for Gaucher disease (GD). The recombinant glucocerebrosidase administered intravenously - usually at biweekly intervals by lifelong has improved the quality of life of patients, avoided spleen removal and bone complications. In the last months an acute shortage of imiglucerase manufactured by the Genzyme Corporation (MA, USA) has occurred as a result of viral contamination firstly and other deficiencies in the production facility. In September 2009 a position statement based on the findings of the European Working Group for Gaucher Disease and European Gaucher Alliance, established a set of key recommendations about identification and monitoring of at-risk patients threatened. In Spain the follow-up of patients and the strict complementation of rules of therapy have permitted to obtain a profile of the situation in a group of patients with restricted ERT. Patients and Methods: A total of 50 GD1 patients have been analyzed before and after 6 and 12 months of imiglucerase shortage. Have been excluded for analysis children in order to dose reduction has been minimal as well as patients who have switched to another ERT or miglustat therapy. Results: Gender: 25 males/25 females. Mean age of group: 45.3±15.3 (range:18-84) SSI at diagnosis(Dx): 8.7±3.8 (range:3-19) Chitotriosidase (CT) activity at Dx:13,383±12,783 nM/mL.h; CCL18/PARC at Dx: 767±1,198 ng/mL. 20% of patients were splenectomized and 78% had bone disease at Dx. During shortage 23 patients (46%) discontinued therapy, in this period only one patient suffered a bone crisis and other anaemia as complications. Mean reduction of haemoglobin level: 2.7% (NS), platelet counts: 5.4% (NS). CT activity was increased 135% (p

Description: Background: The Spanish Gaucher Foundation (FEETEG) is an independent and non-profit organization that keeps the Spanish Gaucher Registry (SGR) established in 1993. This SGR contains demographic, genetic, clinical, analytical and image data from a cohort of 306 Gaucher Disease (GD) patients (269 GD1, 22 GD2, 16 GD3), and 751 relatives. The SGR is a useful tool to perform epidemiological-genetic studies and analyse associated comorbilities. Patients and Methods: From January to July 2006 an epidemiological survey to physicians and to the patients through GD Associations was conducted to ascertain the incidence of neurological symptoms in patients and their relatives as well as analyse genotype-phenotype relationship. The statistical analysis was performed in a SPSS 12.0 database using descriptive parameters, ANOVA, t-test and correlation study including Pearson coefficient. Results: Twenty-four (38.7%) out of 62 GD1 patient respondents from 56 families have neurological symptoms, 8 (12.5%) tremor, 8 (12.5%) uncoordinated movements, 11 (17.7%) concentration defects, 3 (4.8%) strabismus and 8 (12.5%) deafness, 3 (4.8%) Parkinson Disease (PD). Twenty-one out of 56 families have one or more relatives with neurological manifestations. There were 29(8.6%) out of 336 relatives with neurological symptoms:13 (3.8%) PD, 5 (1.5%) epilepsy, 6 (1.8%) essential tremor, 5 (1.5%) others. Subjects with PD were carriers of mutations:: S364R, G202R, V398I, R47X, L336P, L444P, G195W, recNci and insertion alleles. In families with epilepsy the predominant carrier mutations were: L444P, G195W, R130W and in essential tremor: L444P. Comments: There is a high incidence of neurological symptoms between GD1 patients and carriers. These manifestations appear frequently in carriers of rare mutations. It is very recommendable to perform a systematic neurological exam in GD1 patients and in carriers with risk mutations.

Description: Abstract 2871 Deletion at 13q14 (13q) is the most common genomic aberration in CLL. It is present in more than 50% of cases, and is the sole documented cytogenetic abnormality in 36% of the patients. These latter cases are known to have a more favorable clinical course. However, recent data from our group and others, suggest that patients with CLL and 13q deletion as the only FISH abnormality could have a different outcome depending on the number of cells displaying this aberration. Thus CLL patients with a high number of 13q cells usually had both shorter overall survival and shorter time to first therapy. However, to the best of our knowledge the molecular characteristics of these patients have not been so far analyzed in detail. A total of 102 samples were selected for the study, 32 of which served as a validation cohort. A complete immunophenotypic analysis by flow cytometry and FISH studies were carried out in all cases. The median age was 68 years (range, 35 to 90 years). For the purpose of the study, only samples with one cytogenetic abnormality were included. For the gene expression profile analysis, according to our previous results, two groups of patients with 13q were compared: those in whom 80% or more of cells showed 13q (13qH) and those in whom fewer than 80% of cells showed 13q losses (13qL). The distribution of cases in the study cohort was: 13qH (n=25; 36%), 13qL (n=27; 39%), normal FISH (nCLL, n=8; 11%) and 17p/11q (n= 10; 14%); and in the validation cohort: 13qH (n=7; 22%), 13qL (n=11; 34%) and nCLL (n=9; 28%). Peripheral blood mononuclear cells (PBMCs) were isolated from fresh peripheral blood samples using Ficoll gradient, snapfrozen and stored at 80°C. For the validation cohort, CD19positive B cells were purified by magnetically activated cell sorting (MACS) CD19 MicroBeads resulting in a 〉98% purity, as analyzed by flow cytometry. CD19positive normal B cells from peripheral blood of five healthy donors served as controls. All samples were hybridized with the Affymetrix Human Exon arrays 1.0 ST. A total of 3 450 genes significantly distinguished 13qH from 13qL patients, defining the 13qH signature. To determine the biological significance of the deregulated genes, a further analysis was carried out, revealing that apoptosis, BCR and NFkB signaling were the most significant affected pathways in 13qH CLL patients. Moreover, 13qH CLL patients were also characterized by a striking overrepresentation of deregulated miRNAs. A total of 15 miRNAs were deregulated in 13qH relative to 13qL patients. HsamiR155 was the most highly upregulated miRNA (Rfold=3.70), while hsamiR223 was the most significantly downregulated (Rfold=0.10). The posttranscriptional regulatory network of miRNA and genes in CLL patients with more than 80% of 13q cells was carried out by analyzing the miRNAmRNA relationships and the pathway analysis demonstrated that B cell receptor signaling, PI3K signaling and NFkB signaling were among the most strongly affected pathways in 13qH patients, highlighting the importance of miRNA regulation in CLL. The influence of other factors with prognostic relevance in CLL, such as IGVH mutational status, was discarded. We also analyzed the gene signature of CLL high risk cytogenetic subgroups in comparison with 13q patients. Surprisingly, our results suggest that some of the biological characteristics of 13qH CLL patients were similar to those of highrisk cytogenetic subgroups, since they share the deregulation of several key signaling pathways. To validate the differences observed between the subgroups of 13q CLL patients and get a visualization of these, we applied the Principal Component Analysis (PCA) in an independent series of patients. The expression pattern of CD19+ cells from CLL patients was notably different from the gene expression profile of CD19+ cells from healthy donors. Thus, CLL patients with a high number of 13q cells can be differentiated based on their expression profile. By contrast, the gene expression of B lymphocytes from 13qL and normal FISH subgroups was similar. Therefore, this study provides new evidences regarding the heterogeneity of 13q deletion in CLL patients. Thus an overexpression of BCR and NFKB patways and as well as a deregulation of the balance between the proliferative and apoptotic signals and miRNA expression are involved in cases with higher percentages of 13q- cells. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 1776 Array-based sequence capture (Roche NimbleGen) followed by next-generation sequencing (Roche GS FLX Titanium sequencing platform) was used to analyze genetic variations in 93 genes relevant in CLL and two chromosomal regions: 13q14.3 and 17p13.1. CD19+ cells from 4 patients with CLL and 4 patients with other hematological malignancies (used as controls) were studied. A custom-made data analysis pipeline was used to annotate detected variants, including known single-nucleotide polymorphisms (SNPs), amino acid consequences, genomic location and miRNA binding sites. The enrichment assay followed by NGS allowed the detection of over 1600 variations/sample (median 1721, range 1618–1823). All putative variants were first compared with published single nucleotide polymorphism (SNP) data (dbSNP build 130) and most of the variants detected were identified as known SNPs. Overall, 10% of variants detected in each sample were variations not previously described. Interestingly, a 4bp insertion/deletion polymorphism (rs2307842) in the 3′UTR of HSP90B1, target site for miR-223, was detected. There is an increasing evidence suggesting that SNPs in the 3′UTR targeted by miRNAs (known as miRSNPs) are associated with diseases by affecting gene expression. We hypothesized that this ‘GACT’ deletion disrupts the binding site for miR-223 thereby increasing the translation of HSP90B1 and we confirmed that miR-223 regulates HSP90B1 expression by 3′UTR reporter assays. The relative luciferase activity of the construct with wild-type 3′UTR (WT-3′UTR) was significantly repressed by 31% following miR-223 transfection (p

Description: Abstract 1713 Abstract Title: Is azacitidine (AZA) really effective in higher risk MDS patients with chromosome 7 abnormalities (Abn 7)? Results of a retrospective study from the GFM and GESMD registries. Background: Cytogenetic alterations are the most discriminative prognostic variables in MDS, complex karyotype and abnormalities of chromosome 7 (Abn 7) having the poorest outcome. However, prognosis of isolated 7q- and to a lesser extent isolated −7 appears to be less severe than that of complex karyotypes at least in patients not receiving drugs with a potential effect on survival (Schanz et al, JCO, 2012, Cordoba et al, Cancer, 2012). It has been suggested in relatively small patients series that Abn 7 may be associated with relatively favorable response to AZA in MDS. We analyzed the outcome of a large series of higher risk MDS with Abn 7 treated with AZA. Methods: Between 2005 and 2011, higher risk MDS pts were treated with AZA (75 mg/m2/d during 7 or less often 5 days / 4 weeks, scheduled for at least 6 cycles), in compassionate programs (prior to AZA approval by EU) or within AZA label (since 2008) and included in the French and Spanish MDS registries. We retrospectively analyzed, in those series, the outcome of pts with Abn 7. Results: 123 pts with Abn 7 having received at least one cycle of AZA, including 82 (66%) de novo MDS and 69 males (55%), with a median age of 70y (range 33–89) were analyzed. At diagnosis, according to WHO 2008, 52% pts (n=65) had RAEB2, 16% (n=20) had RAEB1 and 10% (n=13) had AML with 20–30% marrow blasts (RAEB-T according to FAB). IPSS was high in 51% (n=64), int-2 in 43% (n=55), and not available (but at least int-2) in the remaining 25 pts. Karyotype distribution was: monosomy 7 (−7) (isolated or with 1 other abnormality, non complex −7) in 33 patients (27%), 7q- (isolated or with 1 other abnormality, non complex 7q-) in 19 patients (16%), del(7p) (isolated or with 1 other abn) in 1 patient (1%), and 69 patients (56%) had complex karyotype (〉= 3 abn) with −7 or 7q-. Among 106 patients with this information available, 74% (n=78) were RBC and/or PLT transfusion dependent (TD). 86% (n=108) of the patients received the conventional 7 day schedule of AZA, the remaining 14% receiving reduced daily dosing or 5 day cycles. The median number of cycles administered was 5 (1–32). Among 110 patients with available information the overall response rate (IWG 2006 criteria) was 32% (35/110), including 12% CR and 20% SD with HI. Among non responders, 12% died prior to evaluation, 33% were in SD and 23% progressed. Among transfusion dependent patients, 16% became RBC transfusion independent (12 of 73 TD patients with available information). The overall response rate was 30% in pts with complex karyotype with −7 or 7q-, 33% in pts with non complex −7 and 31% in pts with non complex 7q- (p=0.1 for complex vs non complex Abn 7). At the time of last follow up, 66 patients (53%) had relapsed or progressed and 102 (83%) had died. Median event free survival(considering death, relapse or progression as events ) at 1 and 2 years was 32 and 8%, respectively. Median OS at 1 and 2 years was 40%, and 18%, respectively. OS was better for patients with response after 4–6 cycles (OS at 1 year 64%) when compared with SD (1y OS 47%) or progression (1y OS 12%), p

Description: Abstract 1704 Gene expression profiling studies have been performed in MDS to better characterize these diseases. However, the molecular pathogenesis of low-risk MDS is not yet fully understood. Furthermore, the transcriptional activity is dependent on many factors including epigenetic modifications. Therefore the integration of genome-wide epigenetic regulatory marks along with gene expression levels would provide additional information regarding the biological characteristics of low-risk MDS. A total of 83 low-risk MDS patients and 36 age-matched controls were included in the study. A cohort of 18 patients with low-risk MDS and seven controls were included in a simultaneous integrative study of methylation and expression, while the whole series was used as a control group of expression data. Both the RNA and the DNA were isolated from BM mononucleate cells and hybridised with the Human Genome Expression Array (U133 Plus) from Affymetrix and MCAM Array from University Health Network (Canada), respectively. For analysis and interpretation of the hybridisation results, the R/Bioconductor program, DAVID bioinformatic resource, the web-delivered bioinformatics tool set Ingenuity Pathway Analysis and Metacore Analytical Suite were used. The results generated by expression and methylation microarrays were confirmed using Q- PCR and pyrosequencing, respectively. A total of 817 differentially methylated genes were identified as being present in low-risk MDS (p〈 0.10); hyper-methylated genes (n=457) were more frequent than hypo-methylated genes (n=360). In addition, mRNA expression profiling identified 1005 genes that significantly differed between low-risk MDS and control group. Integrative analysis of the epigenetic and expression profiles revealed that 66.7% of the hyper-methylated genes were under-expressed in low-risk MDS cases. The most represented categories were regulation of apoptosis, gene expression, immune response and RNA process. BCL2, ETS1, IL27RA and DICER1, all of them hyper-methylated and down-expressed, were the most significant genes related to these functions. 1. Regarding apoptosis and BCL2, an over-expression of BCL2L11 and MYC were found in low-risk MDS. In contrast, BAX and CUX1 were under-expressed with respect to the control group. In addition, SYK gene was also hyper-methylated and under-expressed. 2. Promoter region analysis demonstrated that ETS1 transcription factor was involved in the regulation of 83 target genes included in the down-regulation signature of the low-risk MDS patients. The most significant functions of these target genes revealed that the cell-to-cell signaling and interaction pathway were prominently affected. In addition, apoptosis was identified as the function with the most number of down-regulated target genes. Therefore, the overall apoptosis pathway could be affected in low-risk MDS patients in two ways: methylation and decreased expression of BCL2 with the deregulation of related genes, as well as methylation and decreased expression of the ETS1 transcription factor with the deregulation of the apoptosis-related targets. 3. Regarding immune response, the study showed that besides IL27RA, another nine interleukins and interleukin receptors were under-expressed in the same cohort of patients: IL16, IL32, IL1RAP, IL2RB, IL6R, IL7R, IL10RA, IL10RB and IL13RA1. Three of them (IL16, IL1RAP and IL10RB) had direct genetic interactions with IL27RA. 4. Finally, the identification of DICER1 as a gene significantly altered by methylation and expression in low-risk MDS prompted us to measure the 183 miRNAs expression. A general down-regulation of miRNAs was observed in low-risk MDS cases respect to the control group (p=0.039). Our integrative analysis revealed that aberrant epigenetic regulation is a hallmark of low-risk MDS patients and could play a central role in these diseases. Furthermore, we highlight candidate DNA methylation changes associated with low-risk MDS patients. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction: MCL is a mature B-cell neoplasm characterized by t(11;14) (q13;q32) and cyclin D1 (CCND1) overexpression. Molecular studies have revealed other alterations in cell-cycle regulation, DNA damage response and cell survival pathways, with a landscape of somatic mutations being recently identified. CNS involvement is a well known complication, occurring in 4-26% of MCL at five years, with an ominous significance. Although different clinical variables have been identified as risk factors for CNS infiltration, the biological parameters related to this complication have not been extensively studied. The aim of the study was to explore the biological parameters associated with CNS involvement in a multicentre and retrospective series of MCL patients. Patients and Methods: 285 patients (M:74%; 64 yr) diagnosed of MCL between 1990-2014 (median survival of 4 years) were analysed. In addition to standard clinico-biological variables, IGHV mutational analysis, chromosomal alteration studies and Sanger sequencing of NOTCH1, NOTCH2, TP53, BIRC3, WHSC1, MEF2B, MLL2, TLR2 and PRDM1 were performed. Results: CNS involvement was observed in 15/285 MCL patients (5.2%), with a 5-yr risk of 9.1% (95%CI: 4.6-13.6), one patient at diagnosis, and at first or second/ulterior progressions in 7 cases each. The clinical, pathological and molecular risk factors identified are detailed in the Table. In addition to what has been already described, CNS involvement was usually observed in MCL cases with a clinical nodal presentation (p=0.05). In fact, no indolent MCL with a non-nodal presentation developed this complication during the follow-up period. No differences were observed in the risk of CNS involvement between patients treated in first-line with conventional or high-dose intense treatment (5-yr risk: 6.1%+/-6% vs. 10.7%+/-10.6%, p=ns). Regarding the biological features, no differences in terms of the IGHV mutational status were observed in cases developing CNS involvement compared to the others (75% vs. 68.7%, using 97% identity cut-off). Similarly, the IGHV gene usage of CNS involved cases corresponded to the more frequent IGHV genes observed in MCL (usually IGHV1-18, IGHV3-23, IGHV4-34, IGHV4-59). Although not significant, a predominance of high number copy number alterations (CNA) (〉4) could be observed in the genetic study of MCL cases with CNS involvement as could be expected for the enrichment in blastoid variants (up to 50% of these cases). In fact, we did not observe any case with CNS involvement among those cases with 3 or less CNA. CNS involvement was not related to common poor prognosis genetic alterations such as 9p, 11p and 17p losses, but the presence of 8q gains was associated with a higher risk of CNS involvement (p=0.05). We did not find any significant association between CNS involvement and the large number of oncogenic mutations studied. Conclusions: CNS involvement in MCL is associated with initial aggressive clinico-biological characteristics. Non-nodal MCL cases with a low number of genetic alterations did not present CNS involvement. Finally, the presence of 8q gains was associated with a higher risk of CNS infiltration. Table Initial Clinical Features Category N 5 yr-CNS involvement (%, 95%CI) HR p Performance status (ECOG) 〉 1 8/51 41.5 (+/-28) 4.2 .003 ≤ 1 7/128 9.4 (+/-5.5) Nodal disease Yes 14/185 13.3 (+/-7.6) 6.1 .05 No 1/77 1.4 (+/-2.7) Hemoglobin (g/L) 〈 105 12/93 24.7 (+/-14.7) 3.2 .05 ≥ 105 3/78 5.3 (+/-6.3) LDH 〉 ULN 4/89 27.1(+/-19.4) 6.7 ULN 11/114 21.6 (+/-14.9) 3.5 .04 〈 ULN 3/66 8.7(+/-10) Molecular & Pathological data Histological variant Blastoid 6/58 17.3 (+/-13.7) 3.5 .02 Others 8/156 1.3 (+/-7.2) Ki-67 〉 30% 5/44 17.5 (+/-14.9) 3.6 .06 ≤ 30% 3/61 6.7 (+/-9.4) SOX11 Positive 8/153 2.9 (+/- 5.7) 2.6 ns Negative 1/42 2.1 (+/-2.4) IGHV ≥97% 6/109 9.5 (+/-9.6) 1.9 ns 4 2/87 3.9 (+/-5.7) 1.1 ns ≤ 4 1/44 2.3 (+/-4.3) Chromotripsis Yes 1/17 12.5 (+/-22) 3.2 ns No 2/106 1.9 (+/-2.7) 8q gain Yes 2/30 13.1(+/-19) 7.5 .05 No 2/97 1 (+/-1.96) CNA: copy number alteration; IGHV: immunoglobulin heavy chain; LDH: Lactate dehydrogenase Disclosures No relevant conflicts of interest to declare.

Description: Abstract 2914 Background: Based on clinical and biological data, a multistep model of disease progression starting in monoclonal gammopathy of undetermined significance (MGUS) continuing through MM, sometimes with an intermediate entity called smoldering MM (SMM), and ending in extramedullary disease, has been proposed. Material and Methods: To gain further insights into the role of the transcriptome deregulation in the transition from normal plasma cells (NPC) to clonal PC and from indolent clonal PC to malignant PC, we performed gene expression profiling (GEP) by Human Gene 1.0 ST Array (Affymetrix) in purified PC from 41 patients with MM, 33 with high-risk SMM and 20 with MGUS. In addition, 5 healthy donors were also included in order to relate the deregulation of GEP of clonal populations to normal condition. Results: Initially, we investigated whether the selected PC population from monoclonal gammopathy patients displayed specific GEP that were clearly distinguishable from NPC. 126 common genes were differentially expressed in MGUS, SMM and MM as compared to NPC (q-value 〈 10−5). The two most significant molecular and cellular functional categories were cell cycle and cell death (P 〈 0.01). The top 3 canonical pathways were EIF2 signaling, regulation of EIF4 and p70S6K signaling, and mTOR signaling (P 〈 0.001). Interestingly, 17 and 9 out of the 126 significant deregulated genes were small nucleolar RNA molecules and zinc finger proteins. GADD45A was the most significant up-regulated gene in clonal PC vs NPC. Subsequently, we looked for genes deregulated in MGUS vs MM, SMM vs MM and MGUS vs SMM, in order to identify gene categories and molecular pathways involved in MM development. A total of 1,184 genes were differentially expressed between MGUS and MM (q-value 〈 10−5) with an imbalance in favor of antiapoptotic state in MM. Thus, BAG3, GADD45B, AKT1 and AKT2 were overexpressed in MM while APAF1 and BCL2L1 were underexpressed in MM. The molecular and cellular function most significantly affected in this comparison was cell death with 106 genes involved (P 〈 0.01). One of the top 10 genes upregulated in MM vs MGUS was TERC. In the SMM vs MM comparison, 1,163 genes were deregulated (q-value 〈 10−5). DNA replication, recombination and repair (ATM, RAD17, RAD50) was the most significant deregulated molecular and cellular function. Telomere extension by telomerase and Myc mediated apoptosis were included within the most significant canonical pathways. The analysis showed that a set of 627 differentially expressed genes was able to differentiate MGUS from SMM (q-value 〈 10−5). Cell death was identified as the most significant molecular function affected (P 〈 0.01). The RAC signaling pathway deregulation (P 〈 0.01) was included within the five most significant canonical pathways. In addition, NFKB signaling was also in the top canonical pathways (P 〈 0.01). Finally, we also looked for those genes significantly deregulated among the three entities, which in turn were progressively up or downregulated from MGUS to SMM and to MM. We reasoned that these genes could be the most significant for promoting multistep transformation. Surprisingly, only eight out of the 2,974 significant genes exhibited a progressive deregulation (P 〈 0.0001) in the evolving stages of monoclonal gammopathies (Figure 1). All the genes with a progressive increase from MGUS to SMM and to MM were snoRNA. APAF1, VCAN and MEGF9 showed a progressive downregulation in the transition from MGUS to SMM and to MM. Conclusion: Our data show that although MGUS, SMM and MM are not clearly distinguishable groups according to their GEP, several signaling pathways and genes were significant deregulated in the different steps of transformation process. Disclosures: Lahuerta: Janssen: Honoraria; Celgene: Honoraria. Oriol:Janssen: Honoraria; Celgene: Honoraria.

Description: Abstract 295 Genetic events mediating transformation from the pre-malignant monoclonal gammopathies (MG) to myeloma (MM) are unknown. Previous FISH analyses have highlighted that most genetic lesions typical of MM are already present in MGUS. However, the genetic abnormalities characteristic of each evolving stage of MG have not been elucidated. To obtain a comprehensive genomic profile of MG cases from the early to the late stages we performed for the first time high resolution analysis on purified plasma cells from 20 MGUS, 20 Smoldering MM (SMM) and 34 MM by high density 6.0 SNP-array. Ten matched non-tumor DNA samples were also included in the analysis. We examined DNA copy number alterations (CNA), copy number neutral loss of heterozygosity (CNN-LOH) and the spectrum of minimally altered regions which could contain relevant genes. Moreover, visual inspection allowed us to detect intermediate situations which corresponded to imbalances present in minor populations (less than 50%) coexisting with the major diploid population. CNA were identified in 69 (93%) of the 74 patients analyzed with a median of 8 imbalances per abnormal case. The only 5 cases with no CNA corresponded to asymptomatic entities. We observed a progressive increase in the incidence of genomic imbalances from MGUS (median, 5/case) to SMM (media, 7.5/case) to MM (median, 12/case) (P=0.006; MGUS vs MM). In particular, gains on 1q, 3p, 6p, 9p, 11q, 19, 21q together with losses on 1p, 16q and 22q may be important genetic events associated with MGUS-MM transition, as they were less frequent in MGUS than in MM (P