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PURPOSE In immunoglobulin light chain (AL) amyloidosis, amyloid fibrils cause organ dysfunction. Anselamimab, a monoclonal antibody, selectively binds to amyloid fibrils, accelerating their clearance. METHODS Newly diagnosed patients with European modification of Mayo 2004 stage IIIa or IIIb AL amyloidosis were randomly assigned to receive anselamimab or placebo with cyclophosphamide, bortezomib, and dexamethasone (with or without daratumumab). The primary end point was a hierarchical composite of time to all-cause mortality (ACM) and frequency of cardiovascular hospitalizations (CVHs), analyzed using the Finkelstein-Schoenfeld test and win ratio estimation. RESULTS Among 406 randomly assigned patients, the primary end point win ratio for anselamimab versus placebo was 1.11 (95% CI, 0.83, 1.50; P = .332) and the hazard ratio (HR) for ACM was 0.80 (95% CI, 0.57, 1.13; P = .290). CVH rates in the anselamimab and placebo groups were 0.59 (95% CI, 0.42, 0.83) and 0.89 (95% CI, 0.55, 1.43), respectively ( P = .145). Among patients with kappa isotype (n = 72), the win ratio was 2.06 (95% CI, 0.98, 4.31; P = .100) and anselamimab reduced ACM by 62% versus placebo (HR, 0.38; 95% CI, 0.17 to 0.86; nominal P = .012), and CVH by 71% (IRR, 0.29; 95% CI, 0.10 to 0.87; nominal P = .028) with improvements in Kansas City Cardiomyopathy Questionnaire-Overall Score. There was no clinical benefit observed in the lambda population. Anselamimab was generally well-tolerated; safety data were comparable between treatment arms overall. CONCLUSION Treatment with anselamimab, an antifibril antibody used alongside antiplasma cell dyscrasia therapy, while not meeting the primary end point in the overall population, significantly improved ACM and CVH in patients with kappa AL, potentially offering a new therapeutic option for this isotype.

7501 Background: AL amyloidosis is a plasma cell dyscrasia (PCD) characterized by κ or λ Ig light chain amyloid fibrils that deposit in vital organs. Anselamimab is an investigational mAb designed to complement anti-PCD therapy through accelerated removal of amyloid fibrils. Cardiac Amyloid Reaching for Extended Survival (CARES) studies (NCT04512235 and NCT04504825) investigated the efficacy and safety of anselamimab compared with placebo, in addition to anti-PCD therapy. Methods: Alongside anti-PCD therapy with CyBorD (daratumumab was permitted) newly diagnosed patients with European modification of Mayo stage IIIa or IIIb AL amyloidosis were randomized 2:1 to receive anselamimab (1000 mg/m 2 ) or placebo (normal saline) IV every 7 days for 4 weeks followed by every 14 days for the remainder of the blinded study (18 months after the last participant enrolled). The primary endpoint was a hierarchical combination of time to all-cause mortality (ACM) and frequency of adjudicated cardiovascular hospitalizations (CVH) using the Finkelstein-Schoenfeld test and win-ratio in the combined study population. Subgroup analysis by involved κ or λ free light chain (iFLC) was prespecified. Results: 271 patients were randomized to receive anselamimab and 135 placebo. Baseline characteristics were similar between treatment arms. The median duration of treatment was 21.4 months and 21.1 in the anselamimab and placebo arms, respectively. Daratumumab was used in 79.3% and 83.7% of the anselamimab and placebo arms, respectively. Results of the primary efficacy analyses are shown in the table. Anselamimab-treated patients with κ iFLC had a 62% reduction in ACM (HR = 0.38; 95% CI, 0.17, 0.86; nominal P = 0.012) and a 71% reduction in risk for CVH (estimated CVH rate ratio = 0.29; 95% CI, 0.10, 0.87; nominal P = 0.028). Patients with λ iFLC had a 10% reduction in risk for CVH; none in ACM. Safety data were comparable between both treatment arms. In anselamimab-treated patients, safety findings were similar between κ subgroup and full population. Conclusions: Anselamimab, a κ light chain–directed anti-fibril monoclonal antibody used alongside standard of care chemotherapy, offers a first-in-class, new therapeutic option for patients with newly diagnosed κ AL amyloidosis. Clinical trial information: NCT04512235 and NCT04504825 . Summary of primary efficacy endpoints. Endpoint Overall κ Isotype λ Isotype Anselamimab (N=271) Placebo (N=135) P -value Anselamimab (N=48) Placebo (N=24) P -value Anselamimab (N=219) Placebo (N=109) P -value ACM and CVH win ratio (95% CI) 1.1 (0.8, 1.5) 0.332 2.06 (0.98, 4.31) 0.100 0.9 (0.6, 1.3) 0.848 ACM n (%) 90 (33.2) 52 (38.5) 15 (31.3) 14 (58.3) 73 (33.3) 37 (33.9) HR (95% CI) 0.8 (0.6, 1.1) 0.290 0.38 (0.2, 0.9) 0.012 1.0 (0.7, 1.5) 0.647 CVH Frequency/year (95% CI) 0.6 (0.4, 0.8) 0.9 (0.6, 1.4) 0.145 0.41 (0.2, 0.8) 1.4 (0.6, 3.4) 0.028 0.7 (0.4, 1.0) 0.8 (0.4, 1.3) 0.664 Incidence risk ratio (95% CI) 0.7 (0.4, 1.2) 0.29 (0.1, 0.9) 0.9 (0.5, 1.7)

Introduction: SystemicAL amyloidosis is a progressive and often fatal disease caused by misfolded light chains that aggregate into amyloid fibrils and deposit in vital organs, leading to organ dysfunction. Current standard of care (SoC) therapies for AL amyloidosis target the plasma cell clone to reduce or eliminate light chain production, but do not remove soluble toxic light chain aggregates or insoluble amyloid deposits. Early mortality remains high for patients with advanced disease (e.g., Mayo 2012 Stage IV disease, median overall survival <6 months). Birtamimab - a humanized monoclonal antibody that neutralizes soluble, toxic light chain aggregates and depletes insoluble amyloid deposits by inducing phagocytosis - is under investigation for the treatment of AL amyloidosis. Here, we present a pooled safety analysis from previous Phase 1-3 clinical trials, with a focus on the 2 double-blind randomized controlled trials (RCTs): PRONTO (NCT02632786) and VITAL (NCT02312206). Methods: Patients with AL amyloidosis were treated with intravenous birtamimab up to 24 mg/kg every 28 daysin the non-placebo-controlled Phase 1/2 open-label trial (NCT01707264) with open-label extension (OLE; NCT02613182) and 2 RCTs (Phase 2 PRONTO with OLE [NCT03154047] and Phase 3 VITAL). In PRONTO, patients had received ≥1 previous systemic therapy with at least a partial hematologic response and persistent cardiac dysfunction, and received birtamimab or placebo. In VITAL, newly diagnosed treatment-naïve patients with cardiac involvement received birtamimab + SoC or placebo + SoC (where SoC was a bortezomib-containing chemotherapy regimen). The analysis included all patients who received ≥1 dose of birtamimab. Pooled median exposure times were calculated, and baseline characteristics and demographics were summarized. For VITAL and PRONTO, pooled rates and severity of treatment-emergent adverse events (TEAEs) with birtamimab were compared with rates in the placebo arms. In addition, safety data from the non-placebo-controlled studies were summarized. Results: The median (range) exposure to birtamimab among 302 patients pooled from the Phase 1-3 trials was 12.24 (0.03-57.72) months. Of the 302 patients exposed to birtamimab, 295 received at least one 24-mg/kg infusion, up to 2500 mg. Analysis of the 2 randomized, placebo-controlled trials included data from 196 patients treated with birtamimab from the PRONTO (n=66) and VITAL (n=130) trials and 193 patients who received placebo (PRONTO, n=63; VITAL, n=130). Both trials had comparable treatment durations overall. The rates of TEAEs, serious and grade ≥3 TEAEs were similar between birtamimab and placebo arms within each trial and between treatment arms in the placebo-controlled pooled analysis set (PRONTO and VITAL; Table 1). Higher rates of treatment-related, serious, and grade ≥3 TEAEs were reported in VITAL compared with PRONTO, presumably due to the treatment-naïve population and receipt of concomitant SoC therapy in VITAL. In the pooled analysis set, the most common TEAEs that occurred with greater frequency in the birtamimab vs placebo arms in either trial were, respectively, fatigue (36.2%, 34.2%), diarrhea (33.2%, 33.7%), nausea (31.6%, 30.1%), constipation (31.1%, 31.6%), and dyspnea (25.0%, 24.9%). The most commonly reported (≥5%) serious and grade ≥3 TEAEs were primarily cardiac disorders (cardiac failure, syncope, cardiac arrest), consistent with the underlying disease. Infusion-associated TEAE rates were low in the pooled birtamimab and placebo arms (5.1% vs 3.6%, respectively) and were generally mild to moderate. The safety profile observed in the non-placebo-controlled Phase 1/2 trial plus OLE and PRONTO OLE (n=106) was consistent with the safety data reported in the placebo-controlled studies. Conclusions: Birtamimab was well tolerated in patients with AL amyloidosis when administered as monotherapy and did not demonstrate additive toxicity when given with SoC chemotherapy. Rates of TEAEs in the birtamimab arm were similar to rates in the placebo arm in the PRONTO and VITAL trials. The safety and efficacy of birtamimab is being further investigated in an ongoing confirmatory Phase 3 double-blind RCT in patients with Mayo Stage IV AL amyloidosis (AFFIRM-AL; NCT04973137), which is currently enrolling.

Introduction: Light chain deposition disease (LCDD) is a rare complication of monoclonal gammopathies, defined by non-amyloid linear monoclonal light chain (most commonly kappa) deposits in the kidney and other organs. The rarity of LCDD has hampered clinical studies and staging systems and response criteria are lacking. The International Kidney Myeloma Working Group (IKMG) started a clinical data collection from all participating centers in order to define the natural history of LCDD, and to establish prognostic factors and response criteria in a large, international, unselected patient population. Methods: Eight referral centers have yet participated in the data collection at the data lock of July 31, 2020. Patient inclusion is ongoing and expected accrual is 500 patients. The diagnosis of LCDD had to be biopsy-proven. The patients were diagnosed between 1992 to 2020. Response was assessed 6 months after treatment initiation according to the criteria used in light chain (AL) amyloidosis. Renal survival (RS) was defined as time from diagnosis to dialysis or last follow-up. Patients who died without requiring dialysis were censored at the time of death. The analysis of factors predicting RS was performed in patients whose baseline estimated glomerular filtration rate (eGFR) was >15 mL/min. The cutoffs of baseline variables, as well as the cutoffs measured at the time of response, best predicting RS or OS at 12 months were identified by means of Receiver Operator Characteristics (ROC) analyses. All patients gave written informed consent for their clinical data to be used for research purposes. Results: Overall, 359 patients have been included in this first analysis. Sixteen (4%) subjects had concomitant cast nephropathy. The main clinical characteristics are reported in the Table. Median overall survival (OS) was 13 years and RS was 12 years (Figure1 A and 1B) and median survival of living patients is 4.5 years. At univariate analysis the only baseline variables predicting RS were proteinuria [best cutoff 2.5 g/24h, HR 2.25 (95%CI 1.13-4.60), P=0.02], and eGFR [best cutoff >30 mL/min, HR 0.50 (95%CI 0.26-0.96) P=0.037], but at multivariate analysis only proteinuria predicted RS [HR 2.17 (95% CI 1.08, 4.33), P=0.027]. At univariate analysis, a higher bone marrow plasma cell infiltrate (best cutoff ≥20%) at diagnosis was associated with a significantly lower OS [HR 1.96 (95% CI 1.23-3.13) P=0.004], as was having end stage renal disease (ESRD) defined as an eGFR <15 mL/min [HR 1.81 (95%CI 1.11-2.92) P=0.015]. We then tested the ability of the hematologic response criteria for AL amyloidosis to discriminate groups with different survival after treatment in a 6 months landmark analysis. Our choice of adopting the amyloidosis response criteria was corroborated by the results of the ROC analysis showing that the difference between involved and uninvolved free light chains (dFLC) cutoff (40 mg/L) used in AL amyloidosis to define very good partial response (VGPR) had 87% sensitivity and 65% specificity in identifying patients who needed dialysis within 12 months. Partial response (PR, 19% requiring dialysis at 3 years) was not associated with a RS benefit over no-response (29% requiring dialysis at 3 years, P=0.511). However, VGPR conferred a significant RS advantage (10% requiring dialysis at 3 years) over PR (P=0.002). No significant difference in RS was seen between complete response (CR, 0% requiring dialysis at 3 years) and VGPR (P=0.178). Thus, achieving VGPR or CR by amyloidosis response criteria [post-treatment dFLC<40 mg/L (VGPR by AL criteria), with or without negative serum and urine immunofixation and normal FLC-ratio (CR by AL criteria)] was adopted as a provisional criterion for hematologic response in LCDD (Figure 1D). LCDD response was also associated with prolonged OS (Figure 1C). Conclusions: Almost one-third of patients with LCDD are diagnosed when they already have ESRD resulting in shorter OS. The degree of proteinuria and of bone marrow plasma cell infiltration predict RS and OS, respectively. Achievement of post treatment dFLC <40 mg/L or negative serum and urine immunofixation at 6 months is proposed as a provisional criterion for hematologic response, being able to predict both improved RS and OS. Planned expanded recruitment might allow a validation analysis of the results, the analysis of organ response data and the evaluation of different time-points for response assessment. Disclosures Milani: Celgene: Other: Travel support; Janssen: Other: Speaker honoraria; Pfizer: Other: Speaker honoraria. Kastritis:Pfizer: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Genesis Pharma: Consultancy, Honoraria. Schönland:Janssen, Prothena, Takeda: Honoraria, Other: travel support to meetings, Research Funding. Bridoux:Baxter: Consultancy; Janssen: Honoraria; Celgene: Honoraria. Tuchman:Celgene: Honoraria, Research Funding, Speakers Bureau; Oncopeptides: Consultancy; Amgen: Research Funding; Caelum: Honoraria; Sanofi: Honoraria, Research Funding; Janssen: Research Funding; Roche: Research Funding; Karyopharm: Honoraria, Research Funding. Jimenez-Zepeda:Janssen, Celgene, Amgen, Takeda: Honoraria. Palladini:Jannsen Cilag: Honoraria, Other; Celgene: Other: Travel support. Wechalekar:Celgene: Honoraria; Caelum: Other: Advisory; Janssen: Honoraria, Other: Advisory; Takeda: Honoraria, Other: Travel.

Abstract Waldenström’s macroglobulinemia (WM) is an incurable low-grade lymphoproliferative disorder characterized by bone marrow (BM) infiltration of a clonal population of small B-lymphocytes, plasmacytoid lymphocytes and plasma cells that secrete monoclonal IgM antibody. Because it is difficult to obtain tumor metaphases for karyotype studies, few recurrent chromosomal abnormalities have been reported and the genetic basis of the disease remains poorly defined. Therefore, we performed a comprehensive high-resolution study to identify genomic abnormalities involved in WM pathogenesis. Fifty-seven WM patients were analyzed using a combination of array-based comparative genomic hybridization (aCGH)(N=42); gene expression profiling (GEP)(N=22), DNA sequencing (N=24) and cIgM-FISH (N=57). Agilent 244A and Affymetrix U133 platforms were used in the aCGH and GEP experiments, respectively. An NF-κB index was calculated from GEP data, as a surrogate marker of NF-κB transcription activity. NFKB2 sub cellular localization was determined by immunofluorescence staining. Overall, 83% of samples have aCGH defined chromosomal abnormalities, with a median of 3 abnormalities per patient (range 0 to 27). We identified 16 recurrent regions of copy number change found in >5% (3 or more patients); 10 deleted and 6 amplified regions. The most common abnormality was the entire or partial deletion of 6q, identified in 40% of cases. Four nonoverlapped minimal deleted regions were identified on 6q (MDR1 to MDR4), each of them being present in at least 14 of 17 patients with the abnormality. Gain of 6p was the second most common abnormality (17%) and its presence was always concomitant with 6q loss. Other recurrent deletions were 13q14 (10%) and 7q22, 8p, 11q22-q23, 11q23-q24 and 17p11-p13 (7% each). Copy gains were identified as partial or entire gains of chromosomes 18 (17%), 4 (12%) and 3 (10%), 8q (10%) and Xq27.1-q28 (10%). Three patients had either homozygous deletions or LOH with mutations affecting both alleles of TRAF3 on 14q32. TRAF3 inactivation was correlated with an increased NF-kB transcriptional signature and it was associated with activation of the non-canonical NFkB pathway. Additionally, we identified the inactivation of TNFAIP3, another negative regulator of the NF-kB pathways, in one of 24 patients. Finally, interstitial deletions identified in 4 patients at 13q14 identified a 1.1 Mb MDR, including MIRN15A and MIRN16-1. These findings confirm that focal 13q14 deletion is not restrict to B-CLL and that the MIRN15A/MIRN16-1 abnormalities might be common to several indolent B-cell diseases. Overall, we identified TRAF3 and TNFAIP3 inactivation in 5.3% and 2.4%, respectively. To our knowledge, this is the first study showing the inactivation of bona fide tumor suppressor genes in WM patients. Furthermore, these genes are negative regulators of NF-kB signaling pathway, highlighting its biologic importance in sustaining and limiting growth in WM. Mutational activation of this pathway, which is normally activated by ligand-receptor interactions within the BM microenvironment, suggest a therapeutic role for inhibitors of NF-KB pathway activation in the treatment of WM.

Abstract Background Multiple myeloma (MM) is presently an incurable plasma cell (PC) malignancy which involves 16 000 new patients per year in US. In spite of the abundance of cytogenetic information, with more than 600 published karyotypes in Non-hyperdiploid MM (NHMM), very little is known about the mode of karyotypic evolution or of the presence of possible cytogenetic pathways. In our investigation, we have used 647 NHMM karyotypes, to identify the most frequently occurring imbalances. Patients and Methods The Mitelman database of Chromosome aberrations in cancer (Mitelman et al., 2007) was searched, and myelomas with modal chromosome number less than 48 were selected. All karyotypes were described using ISCN nomenclature (ISCN, 1995). Only the main clones were analyzed and incomplete karyotypes were excluded. The following information was obtained from each karyotype: chromosome number, imbalances including whole chromosome gains and losses; specific translocations and breakpoints, including add chromosomes. An Excel spreadsheet in which the rows of the first column were labeled to represent each band of a 360-band human chromosome ideogram was created as previously described (Hoglund et al., 2001; Horsman et al., 2003) All karyotypes were scored individually in successive columns for net gain and loss of each chromosome band. The total number of gains and losses affecting each chromosome band for the total cohort of karyotypes was then calculated using the Excel countif function. Recurrent abnormalities were defined as those that were involved in >5% of cases. Histograms of the number of abnormalities per tumor were then plotted, and the modal value extracted as variable called time to occurrence. Statistics correlation between the presence and absence of different abnormalities was analyzed using Spearman correlation matrices. P value of <0.05 was considered as statistical significant. Results In total 647 cases of newly diagnosed NHMM were included in the analysis. The median chromosome number was 43. Few cases had chromosome numbers under 40. The median NAPT was 12 (1–49) with a normal distribution (Fig 1). The most common abnormalities were monosomies of the chromosomes 13 and 14 (32.44% and 14.88% respectively). Out of 647 cases, more than 300 NHMM cases contained translocations in their karyotypes. The most common translocation was t(11;14), which occurs in 17% of cases followed by t(1;16) in 2.7% of cases and t(4;14) and t(8;14) in 1.5% respectively. The most recurrent breakpoints in our series include: 14q32 (32%), 11q13 (20%), 1q10 (10.5%), 1q12 (8%), 8q24 (6.9%), 1p11 (6.6%) and 1q21 (5.5%). Discussion Although only about 40% of MM has informative karyotypes, karyotyping has the advantage of representing global genetic changes at the cellular level. In this comprehensive survey, loss of chromosome 13 and 14 were the most common abnormalities. The NAPT analysis suggests that most NHMM patients have at least 12 abnormalities at diagnosis. It is possible that accumulation of abnormalities above a threshold results in malignant transformation. In our series the t(11;14) translocation appears to be the most recurrent translocation and exceeds the rate reported in Hyperdiploid-MM (17% vs 3.8%). Figure 1. NAPT Distribution in NH-MM Figure 1. NAPT Distribution in NH-MM

Abstract Table 1. Samples to p53 deletions p 53 deletion FISH aCGH FISH and aCGH MGUS 142 - - SMM 108 - - Newly diagnosed MM - 182 - Relapsed/refractory MM 62 156 19 HMCLs - 48 - Total 312 386 19 Background: Inactivation of p53 by mutation or allelic loss is a rare event in multiple myeloma (MM) at the time of disease diagnosis and believed to be more common in the late stages of the disease. Here we defined the prevalence of p53 deletions in monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), newly diagnosed MM, relapsed MM and human myeloma cell lines (HMCLs). Indirect mechanisms of p53 inactivation such as amplification of MDM2, or deletion of CDKN2A (p14ARF) were also investigated. Patients and Methods: A total of 631 MM samples and 48 HMCLs were analyzed for p53 abnormalities (Table 1) and compared with a cohort of plasma cell leukemia (PCL) previously published by us. Interphase fluorescence in situ hybridization (FISH) and highresolution array-based comparative genomic hybridization (aCGH) were used to detect p53 deletions. MDM2 amplification and p14ARF loss were evaluated by aCGH. Overall survival (OS) was estimated through Kaplan Meier method. Results: The prevalence of p53 deletions was 1.4%, 3.7%, 8.9%, 20% and 87.5% in MGUS, SMM, newly diagnosed MM, relapsed MM and HMCLs respectively (Figure 1). Of interest patients in first relapse showed a p53 deletion prevalence of 18% in comparison with 33% for patients in second relapse or more. We obtained p53 deletion status in 8 patients noted to have deletion at the time of relapse and in whom we had previous samples stored. In 7 of 8 cases deletions had been acquired (absent in the previous samples). The median OS for relapsed MM patients with or without p53 deletion were 4.2 months and 37.8 months respectively (p <0.001). MDM 2 amplification and p14ARF loss was detected in 0.4% and 2% of new diagnosed MM, 0.6% and 5.1% of relapsed MM and 2% and 29% of HMCLs respectively. Discussion: Emergence of p53 deletion/mutations denotes progression genetic events in MM. Importantly we show for the first time the overriding importance of p53 deletions as prognostic markers in relapsed MM. A molecular staging system that is based on the presence of p53 inactivation may be more powerful than classifying patients based on the loss of p53. Other abnormalities involving p53 pathway regulators like MDM2 gain and p14ARF loss are infrequent events in MM, even in advanced disease. Figure 1. Prevalence of p53 deletions Figure 1. Prevalence of p53 deletions

Abstract Multiple Myeloma (MM) is the second most prevalent haematological disorder in the US with great recent progress propelled by various technological and therapeutic advances. Nevertheless, the complexity of MM genomes remains inadequately characterized. We have combined high-resolution (44K Agilent) array comparative genomic hybridization (aCGH) and gene expression data with clinical outcomes in an initial attempt at indexing genomic complexity in MM and its clinical implication in 100 MM patients. We enumerated the Number of Aberrations per Tumor (NAPT) as defined by the ADM-1 algorithm available within CGH Analytics. There appear to be no difference in degree of genetic complexity between hyperdiploid and non-hyperdiploid myeloma. Generally, t(11;14) have low NAPT whereas D2 tumors have high NAPT. Amongst the high-risk genetic subtypes, tumors with maf translocations have relatively low NAPT whereas t(4;14) have high NAPT. Whilst a Multivariate Cox Proportional Hazards regression of survival outcome showed little statistical support for popular indicators such as ploidy and TC classification, results for NAPT were considerably more encouraging (p~ 0.07, median survival of 40 months in low complexity vs 18 months in high). Log-rank tests further supported prognosis based on NAPT independent of clinical status and ploidy. To characterize complexity, we clustered aCGH profiles by clinical status, ploidy and TC classification. Clear patterns of aggregation and recurrent aberration were observed suggesting that they were possibly instrument to aberrant gene expression. Indeed, expression of a large proportion of genes approximately 2Mb of the recurrent breakpoints varied significantly between patients carrying aberrations vis-a-viz others that did not. Comparison against known gene sets showed an enrichment for cell-cycle and apoptosis genes. We are presently characterizing several such breakpoint-associated genes for their functional significance.

Abstract Background B-cell chronic lymphocytic leukemia (B-CLL) is a well-defined clinical entity with heterogeneous molecular and cytogenetic features. Chromosome aberrations could be associated to specific CLL clinical features and outcomes and their impact on clonal evolution should have been addressed by using temporal analysis. In order to demonstrate the role of temporal analysis in CLL we conducted a comprehensive karyotypic survey of a large number of CLL cases with already known genetic aberrations to fully describe their meaning in terms of biological evolution. Methods A total of 1749 karyotypes were retrieved from the Mitelman Database of Chromosome Aberrations in Cancer. A matrix depicting the 360-band human chromosome ideogram was created. Regions that were either lost or gained in more than 3% of the cases were retained and identified as recurrent imbalances. Early and late imbalances were defined according to the appearance on the complex karyotypes. Descriptive statistics were used to summarize the genetic abnormalities. Results The median chromosome number and the median number of abnormalities per tumor (NAPT) were 46 and 1 respectively. (Figure 1 A and 1B) The most common abnormality seen was trisomy 12 which occurred in 29% (508 cases) followed by 13q14del (10.34%), 13q13del (6.63%) and add14q32 (6.63%). The temporal analysis revealed +12, 13q-, −17, 17p-, −Y and −X to be early imbalances (TO<5), followed predominately by a late loss with TO=5–10.5 (11q-). Hierarchical clustering suggested there are different groups including: trisomy 12, 13q-, 11q-, and 6q-, which at least in this clustering analysis appeared to be mutually exclusive. In summary, we can conclude that overall CLL is a neoplasia that shows remarkable chromosome stability even when only abnormal karyotypes are evaluated. Interestingly, clustering analysis suggests there are non-overlapping, unique subsets of CLL cases where trisomy 12 is the most common and along with 13q-emerged as early events on CLL clonal evolution. Figure 1A. Chromosomes distribution in chronic Lymphocytes Leukemia karyotypes Figure 1A. Chromosomes distribution in chronic Lymphocytes Leukemia karyotypes Figure 1b. Chronic Lymphocytes Leukemia and Number of Abnormalities Per Tumor (NAPT) distribution Figure 1b. Chronic Lymphocytes Leukemia and Number of Abnormalities Per Tumor (NAPT) distribution Figure Figure

Abstract Background Waldenström macroglobulinaemia (WM) is an uncommon indolent B-cell lymphoproliferative characterized by bone marrow infiltration by lymphoplasmacytic cells and an IgM paraproteinemia. This study analyzed the impact of cytogenetics in WM and the pattern of evolution in 73 cases from the Mitelman database and 14 cases evaluated at the Mayo Clinic Arizona (MCA). Patients and Methods The Mitelman database of Chromosome aberrations in cancer (Mitelman et al., 2007) was searched, and 73 WM karyotypes were selected. We also evaluated 14 cases seen at MCA with karyotype analysis at diagnosis. An Excel spreadsheet in which the rows of the first column were labeled to represent each band of a 360-band human chromosome ideogram was created as previously described (Hoglund et al., 2001; Horsman et al., 2003) All karyotypes were scored individually in successive columns for net gain and loss of each chromosome band (loss=0 and gain=1). Recurrent abnormalities were defined as those that were involved in >5% of cases. Histograms of the number of abnormalities per tumor (NAPT) were then plotted, and the modal value extracted as variable called time to occurrence. Statistics correlation between the presence and absence of different abnormalities was analyzed using Spearman correlation matrices. P value of <0.05 was considered as statistical significan Results In total 73 cases of newly diagnosed WM from the Mitelman database were included in the analysis. The median chromosome number was 46 (Range 40 to 49).The most common abnormalities were loss of 6q21 (10%) (Fig 1), +3 (7.1%), loss of X (6%) and −10, −20, −21, +12, +18 and +5 (5.71% respectively). The most common translocation was t(8;14) (4%).The most recurrent breakpoints in our series include: 14q32 (6%), 6q21 (5%), 8q24 (5%), 18q21 (4%) and 19q13 (4%). In the MCA cohort, 14 karyotypes were reviewed and only 3 cases exhibited an abnormal result. Deletion of 6q21, 20q11 and a Robertsonian translocation t(13;14) were reported (3/11, 21%). In the 6q21 case, FISH analysis confirmed the deletion of BLIMP1 on 6q. One case exhibited a 20q deletion in a WM with kidney amyloidosis patient. Discussion In this comprehensive analysis we show a very small complexity of recurrent abnormalities expressed by conventional karyotype analysis in WM. The incidence of 6q21 deletion was 10% by conventional cytogenetics and it is been reported as high as 34% when analysed by FISH (54% when cytoplasmic immunoglobulin M-FISH was used). Interestingly we report the case of a patient with 20q deletion at diagnosis in the MCA cohort. To date, only a limited number of cases with del(20q) as a sole cytogenetic anomaly have been reported in plasma cell dyscrasias, either at diagnosis or later in the disease course. The recurrent immunoglobulin gene translocation is known to be involved in the initial oncogenetic events in plasma cell dyscrasias and, so it is important to identify whether there are any masked translocations involving immunoglobulin genes and 20q in these cases. Figure 1. 6q21 deletion and Waldenstrom Macroglobulinaemia Figure 1. 6q21 deletion and Waldenstrom Macroglobulinaemia