ALBERT

Description: Background: De-ubiquitinating enzyme BAP1, a fundamental deubiquitinase in the epigenetic regulation of transcription factors and functionally related to ASXL1, is mutated in a hereditary cancer syndrome with increased risk of mesothelioma and uveal melanoma. In a recent murine study, absolute BAP1 depletion generated specimens with similar characteristics to myelodysplastic / myeloproliferative syndromes in humans (ineffective hematopoiesis and myeloproliferation), mainly to chronic myelomonocytic leukemia (CMML) (Dey, et al. Science 2012). Aim: The aim of this study was to quantify BAP1 gene expression in patients diagnosed with a variety of myeloid neoplasms, and compared it with healthy donors. We furthermore explored the possible association of BAP1 low expression level and the presence of ASXL1 mutations or BRCA1 protein levels. In addition, a regression analysis to determine the possible correlation of peripheral blood and bone marrow expression levels was performed. Methods: We included patients diagnosed between 2008-2014 of CMML, myelodysplastic sydrome (MDS) chronic myeloid leukemia (CML) and acute myeloid leukemia (AML), of whom bone marrow DNA and RNA were available at diagnosis. As controls, 6 healthy bone marrow donors were used. BAP1 and BRCA1 expressions levels were quantified by RT-qPCR, using the same healthy bone marrow donor sample as an inter-assay normalizing- calibrator. The study of somatic ASXL1 mutations was carried out by the Sanger method. For statistical studies, the T-Student, Pearson correlation and/or U Mann-Whitney test, were used when needed. For survival analysis COX regression and the ROC curves were used. A two-side P

Description: Background and Aim: Azacitidine have shown clinical activity in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), particularly at low, non-cytotoxic doses favoring hypomethylation over cytotoxicity. Cancer/testis antigens (CTAs, encoding for immunogenic proteins which are normally expressed in the testicles and trophoblastic cells of the ovary, have been shown to undergo derepression after the use of demethylating agents in cancer cell line models. We took advantage of the unique model of Aza-treated high risk MDS to in vivocharacterize candidates for immunotherapy following hypometilating therapy. Methods:Targeted RNA-Seq (tRNA-Seq) designed to capture 214 CTA genes was performed in 19 MDS or CMML patients at day 0 and at day +28 after first AZA cycle. In 10 patients the analysis was extended to third and/or four cycles. Sequencing, coverage, mapping and alignment was performed using the Ion Torrent Browser Suite. We used LIMMA package or empirical analysis of digital gene expression data in R (edgeR) to identify differential expressed genes. A homogeneous treatment schedule with AZA (75 mg/m2/day x 7 days) was received by each patient.The response criteria were from IWG 2006, including a bone marrow and cytogenetic reevaluation after 6 cycles. The main candidates selected from de tRNA-seq experiment were characterized at protein level in cell lysate and/or plasma by Western Blot. Primary antibodies used from Thermo Fisher were: ADAM29, DDX53, PRAME, B-TUBULINA, FAM46D, B-ACT, TMPRSS12, MAGEB4, GAPDH, MAGEA1, MAGEA2, TSPY2, Cxorf48, DNAJB8, NY-ES0-1, CT83/Cxorf61 and TFDP3 from Santa Cruz Biotechnology. We used either cell lysate or plasma to study the protein levels in non-reducing SDS-PAGE at different acrylamide concentration depending on the protein size. ImageJ was used to quantify protein levels. Results:The median age of the cohort was 69 (range 48-81 years). The cohort consisted of 16 MDS and 3 CMML patients. MDS Patients were stratified based on IPSS as low or intermediate-1 (n=14) and intermediate-2 or high (n=2) risk groups and CMML patients based on a CPSS of intermediate-2 (n=3). Five patients were classified as complete responders achieving a complete cytogenetic and/or marrow remission (CR). Regarding the tRNA-Seq, on average, we achieved 3.888.308 mapped reads per sample (p25-p75, 1.2x106 - 5.9x106) which represents a sufficient depth for digital gene expression profiling of 214 genes. CTAs re-expressed significantly after one AZA cycle in complete responders were TFDP3 (FC=6,4), ZNF645 (FC=2), MAGEB4 (FC=3,1), MAGEA5 (FC=2), DDX53 (FC=2), VENTPX1 (FC=5,5), TSPY2(FC=3,4) and TSYP3 (FC=3,5). Other potential candidates with significantly re-expression in any responders vs. non responder were:SLCO6A1, ADAM29, DDX53, PRAME, FAM46D, TMPRSS12, MAGEA1, MAGEA2, Cxorf48, DANJB8, NYESO-1 and CT83. In the western-blot experiments, protein expression, longitudinally measured in peripheral blood lysate and/or plasma showed a parallel dynamic to gene expression in the case of TFDP3and DDX53. Conclusions:In this study, targeted RNA-seq is shown as effective and accurate tool to detect weakly expressed transcripts as CTAs. In this work, TFDP3 and DDX53, validated at proteomic level, emerge as most promising candidates for immunotherapy in combination with hypomethylating agents in MDS patients. Disclosures No relevant conflicts of interest to declare.

Description: Background and Aim:It is increasingly recognized that patients with a de novomyelodysplastic syndrome (MDS) onset as young adults, lacking any other feature of a congenital disorder, may share a pathogenic overlap due to the presence of both germline and somatic variants. Identifying an inherited pathogenic variant has important therapeutic implications beyond family counselling: adapting the selection of sibling donor, the use of highly cytotoxic therapy and the monitoring for other cancer development. However, most studies have focused on patients with suspected inherited disorders based on the presence of physical abnormalities and/or family history. In addition, a mixture of pediatric and adult cases is usually reported. The aim of this study is to characterize the germline and tumor variants in a group of adult MDS patients without accompanying congenital physical anomalies and or family antecedent of bone marrow failure. Methods: We included 72 patients from 15 Spanish centers with a diagnosis of MDS between 18 and 60 years old (y.o). Patients with a previously diagnosed or suspected (one physical anomaly or family history) congenital syndrome were excluded. Diagnoses were made in accordance with the WHO 2016 classification. Whole-exome sequencing (WES) libraries were prepared using SureSelectXT Target Enrichment and sequenced on a HiSeq4000 platform (IlluminaInc.). Mean number of reads per sample was 138,726,017 with a Phred Quality Score 〉30 in 95.05% of bases. Read mapping sequence alignment and variant calling were performed using Biomedical Workbench (Qiagen). WES was performed on 72 tumor and 32 paired germinal DNA (buccal swab). To identify potential germline-causal mutations, a selection tool was implemented incorporating 239 genes associated with cause or predisposition to bone marrow failure or cancer. Variants with an ExAC, TOPMed and/or European 1000 Genomes minor allele frequency ≥0.01 were discarded. Results: The median age at diagnosis was 49 y.o. The cohort was categorised into two groups, less or equal 50 y.o. (62.5%) and between 50 and 60 y.o. (37.5%). In the first group, the frequency according to the WHO classification were 12% MDS with single lineage dyplasia (MDS-SLD), 8% MDS with ring sideroblasts (MDS-RS), 11% MDS with multilineage dyplasia (MDS-MLD), 24% MDS with excess blasts(MD-EB), 4% MDS with isolated del(5q)(MDS-del5q), 4% MDS unclassifiable and 4% chronic myelomonocytic leukemia (CMML). Meanwhile, in the group with age more than 50 y.o., the subtypes were 3.7% MDS-SLD, 7.4% MDS-RS, 29.6% MDS-MLD, 40.7% MD-EB, 3.7% MDS-del5q, and 14.8% CMML.Patients less or equal 50 y.o. were stratified based on IPSS-R as very low (4%), low (64%), intermediate (20%), high (12%) and very high (0%); and the group of more than 50 y.o. as very low (14.8%), low (33.3%), intermediate (29.6%), high (11.1%) and very high (11.1%).The mean number of somatic mutations was 0.68 in patients with less or equal 50 y.o. and 1.37 in those between 50 and 60 y.o., p=0.033 (U Mann-Whitney); and regarding germline variants, the first group mean number was 2.44 (p25-75, 1-3) and the second group showed a mean of 1.85 (QI 25-75, 1-3), p= 0,331.In the whole cohort, germline variants were found in 62 out of 72 patients, with the following frequencies: ATR(N=5, 6.9%), followed by BARD1(N=5, 6.9%), ERCC6L2(N=4, 5.6%), MSH6(N=4, 5.6%), TCIRG1(N=4, 5.6%), NBEAL2(N=4, 5.6%), ASXL1(N=3, 4.2%), ATM(N=3, 4.2%), MPL(N=3, 4.2%), NF1(N=3, 4.2%), RECQL4(N=3, 4.2%), SAMD9L(N=3, 4.2%), WRN(N=3, 4.2%).Among germline variants, those reported previously as pathogenic or likely pathogenic, or involving genes associated with familial MDS/AML included: ERCC6L2(N=4, 5.6%), SAMD9L(N=3, 4.2%), and one case mutated for DDX41, FANCC, JAK2, MSH6, SETBP1, MUTYH, BRCA1and RECQL4. In the whole cohort, somatic variants were found in 38 patients, with the following frequencies: TP53(N=7, 9.7%), ASXL1(N=7, 9.7%), SETBP1(N=5, 6.9%), NF1(N=5, 6.9%), SRSF2(N=4, 5.5%). Conclusion:In this subset of young adults with de novo MDS without congenital anomalies and/or familial history suggesting the presence of an undiagnosed congenital syndrome, 18% of the cohort harbored a likely causative germline variant. In addition, we noted a predominance of variants affecting genes with a cancer predisposition limited to the hematopoietic system, rather than classical telomere, DNA damage genes with an established mendelian link. Table. Table. Disclosures Díez-Campelo: Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Description: Background and Aim: The entity defined by the WHO 2017 classification as myeloid neoplasms with germinal predisposition without preexisting disorder or organ dysfunction is particularly interesting within myelodysplastic syndromes (MDS) for three main reasons: i) in myeloid disease derived from congenital bone marrow failure, therapeutic strategies (e.g., type of conditioning regimen) are defined; it is not the case within the group of young patients with MDS harbouring germinal variants, actually a group candidate for allogeneic transplantation of hematopoietic progenitors, ii) its incidence exceeds the cases secondary to congenital bone marrow failure, and iii) the implications of genetic counseling to patients and relatives are yet to be defined and have not been addressed at the time of diagnosis of MDS. Methods: Whole exome sequencing (WES) was performed on 118 tumour and 73 paired germinal DNA from patients of 16 Spanish Group of MDS (GESMD) centers, diagnosed with de novo MDS between 16-60 years old without previous organ dysfunction. WES libraries were sequenced on a HiSeq4000-NovaSeq6000-Illumina platform, mean number of reads per sample was 144,429,985 with a Phred Quality Score 〉30 in 94% of bases and a 100x average depth. To identify potential germline-predisposing mutations, a selection tool incorporating 279 genes associated with cause or predisposition to bone marrow failure or cancer was implemented. The analysis of the variants was carried out by means of an in house pipeline: filtering out intronic, synonymous, and those variants with minor allele frequency (MAF) in the general population 〉1% (ExAC, 1000 Genomes-phase3, TOPmed), and requiring the presence both in tumour and germline DNA with a VAF〉37%. In 45 cases without germline material the last requirement was substituted by not being reported as somatic in COSMIC in any cancer. To determine pathogenicity we followed conservative criteria: a CADD Phred score ≥20 and to be considered deleterious in, at least, three out of six used algorithm. Results: In 118 patients, the median age at diagnosis was 47 years with the following WHO 2017 diagnoses: 12% MDS-SLD, 9% MDS-RS, 34% MDS-MLD, 30% MDS-EB, 3% MDS-del(5q), 1%MDS-U, 11% CMML. We found deleterious/pathogenic germ variants in 68 of 118 patients. Strikingly, we found a higher frequency than expected, for this specific subset, in genes not yet considered in the category of myeloid neoplasms with germline predisposition: MSH6 (n=5;4.2%), ATR (n=5;4.2%), ERCC6L2 (n=4;3.4%), PMS2 (n=2; 1.6%), MLH1 (n=3;3.5%), HCLS1 (n=2;1.7%), ITGB3 (n=2;1.7%), LYST (n=4; 3.4%), SAMD9 (n=1;0.8%), MSH2(n=1;0.8%). In genes already considered in the category of myeloid neoplasms with germline predisposition: MPL (n=2;1.7%), DDX41 (n= 2;1.7%), RUNX1 (n=1; 0.8%), ANKRD26 (n=1;0.8%). We also detected 10 cases with deleterious germline variants in genes related to Fanconi anemia (BRIP1, FANCC, FANCD2, FANCG, FANCM, SLX4, XRCC2, RAD51C and BRCA2), 2 cases with a germline variant in a Shwachman-Diamond gene DNAJC21 (1.7%), and 3 cases with germline variant in a telomere biology gene (RTEL1, CTC1 and TERT). We then focused on the characterization of the variants found in 5 genes not considered to date as predisposing to MDS: MSH6, MSH2, MLH1, ATR and PMS2 involved in the instability of microsatellites and whose alteration determines genomic instability and predisposition to a different number of solid tumors. The frequency of patients carrying these variants (13.5%) is much higher than the frequency of DDX41 (1.7%) or CEBPA (not found in our cohort), the two genes currently considered in the category with germline predisposition without a preexisting disorder or organ dysfunction. The sixteen patients carrying these mutations were characterized by a median age of 47 (16-60) years with the following diagnoses, 33% MDS-MLD, 27% MDS-EB1 and 40% CMML, presenting up to 40% with decrease cellularity in the bone marrow. Conclusions: We describe, for the first time, a high frequency of germinal variants in genes that drive genomic instability by modulating the microsatellite pathway, in young adults diagnosed with MDS without previous organ dysfunction. Their frequency and high pathogenicity index warrant functional validation experiments and pose them as potential candidates to be included in future classifications and to be considered in clinical, therapeutic and genetic counseling strategies. Disclosures Díez-Campelo: Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Sanz:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onconova: Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffman - La Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen - Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Jerez:Novartis: Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Description: Criteria of response and definition of resistance and intolerance to hydroxyurea (HU) in polycythemia vera (PV) were proposed by the European LeukemiaNet (ELN). Such criteria were evaluated in 261 PV patients (median follow-up, 7.2 years) treated with HU for a median of 4.4 years. Complete response, partial response, and no response were observed in 24%, 66%, and 10% of patients, respectively. Achieving ELN response (complete or partial) or hematocrit response did not result in better survival or less thrombosis and bleeding. On the contrary, having no response in leukocyte count was associated with higher risk of death (HR, 2.7; 95% confidence interval [CI], 1.3%-5.4%; P = .007), whereas lack of response in platelet count involved a higher risk of thrombosis and bleeding. Resistance and intolerance to HU was registered in 11% and 13% of patients, respectively. Resistance to HU was associated with higher risk of death (HR, 5.6; 95% CI, 2.7%-11.9%; P 〈 .001) and transformation (HR, 6.8; 95% CI, 3.0%-15.4%; P 〈 .001). In summary, fulfilling the ELN definition for response to HU was not associated with a benefit in the clinical outcome in PV, whereas response in platelet and white blood cell counts were predictive of less thrombohemorrhagic complications and better prognosis, respectively. Resistance to HU was an adverse prognostic factor.

Description: Introduction: Patients (pts) with CLL may be at particular risk of severe COVID-19 given advanced age and immune dysregulation. Two large series with limited follow-up have reported outcomes for pts with CLL and COVID-19 (Scarfò, et al. Leukemia 2020; Mato, et al. Blood 2020). To provide maximal clarity on outcomes for pts with CLL and COVID-19, we partnered in a worldwide effort to describe the clinical experience and validate predictors of survival, including potential treatment effects. Methods: This international collaboration represents a partnership between investigators at 141 centers. Data are presented in two cohorts. Cohort 1 (Co1) includes pts captured through efforts by European Research Initiative on CLL (ERIC), Italian CAMPUS CLL Program, and Grupo Español de Leucemia Linfática Crónica. The validation cohort, Cohort 2 (Co2), includes pts from US (66%), UK (23%), EU (7%), and other countries (4%). There is no overlap in cases between cohorts. CLL pts were included if COVID-19 was diagnosed by PCR detection of SARS-CoV-2 and they required inpatient hospitalization. Data were collected retrospectively 2/2020 - 5/2020 using standardized case report forms. Baseline characteristics, preexisting comorbidities (including cumulative illness rating scale (CIRS) score ≥6 vs.