Citations

AbstractPlasma cell neoplasms (PCN) and mantle cell lymphoma (MCL) can both harbor t(11;14)(q13;q32) (CCND1/IGH), usually resulting in cyclin D1 overexpression. In some cases, particularly at low levels of disease, it can be morphologically challenging to distinguish between these entities in the bone marrow (BM) since PCN with t(11;14) are often CD20‐positive with lymphoplasmacytic cytology, while MCL can rarely have plasmacytic differentiation. We compared the difference in CCND1/IGH by fluorescence in situ hybridization (FISH) in PCN and MCL to evaluate for possible differentiating characteristics. We identified 326 cases of MCL with t(11;14) and 279 cases of PCN with t(11;14) from either formalin‐fixed, paraffin‐embedded tissue or fresh BM specimens. The “typical,” balanced CCND1/IGH FISH signal pattern was defined as three total CCND1 signals, three total IGH signals, and two total fusion signals. Any deviation from the “typical” pattern was defined as an “atypical” pattern, which was further stratified into “gain of fusion” vs “complex” patterns. There was a significantly higher proportion of cases that showed an atypical FISH pattern in PCN compared with MCL (53% vs 27%, P < .0001). There was also a significantly higher proportion of cases that showed a complex FISH pattern in PCN compared with MCL (47% vs 17%, P < .0001). We confirmed these findings using mate‐pair sequencing of 25 PCN and MCL samples. PCN more often have a complex CCND1/IGH FISH pattern compared with MCL, suggesting possible differences in the genomic mechanisms underlying these rearrangements in plasma cells compared with B cells.

7022 Background: Philadelphia-like Acute Lymphoblastic Leukemia (Ph-like ALL) is a high-risk subset of adult ALL. Until recently, there has not been a systematic platform to recognize this entity in clinical practice. Furthermore, data regarding the role of allogeneic hematopoietic cell transplantation (allo-HCT) is lacking. We conducted this study to identify patients with Ph-like ALL and describe their outcomes in comparison to Ph+ and Ph- ALL with emphasis on the role of allo-HCT. Methods: To identify cases of Ph-like ALL, available diagnostic cytogenetic pellets for patients in the Mayo Clinic ALL cohort (N=365) were tested using a targeted fluorescence in situ hybridization (FISH) panel developed by the Mayo Clinic Genomics Laboratory and includes probes to detect Ph-like-specific rearrangements (i.e., ABL1, ABL2, PDGFRB, JAK2 and CRLF2). Results: Thirty-three (9%) patients with Ph-like ALL were identified, the remaining patients were classified as Ph+ (N=132, 36%) or Ph- ALL (N=200, 55%). Patients with Ph-like ALL were younger (Median: 39 vs. 50 vs. 49 years, P=.01), had higher WBC (Median: 27.9 vs. 21.5 vs. 4.5 x109/L, P<.001), were less likely to achieve CR (91% vs. 99% vs. 96%, P=.02), more likely to be MRD+ (64% vs. 34% vs. 36%, P=.03), had a higher relapse rate (5-year: 39% vs. 24% vs. 38%, P=.01) and lower OS (5-year: 41% vs. 64% vs. 49%, P=.02), see Table. Patients who achieved MRD negativity had better OS (MRD+ vs MRD-, P=.01). Importantly, no statistically significant difference in OS, relapse or non-relapse mortality were noted between the 3 groups in patients who underwent allo-HCT in CR1. Conclusions: Ph-like ALL is a high risk subgroup with increased prevalence in younger adults. Allo-HCT appears to offset the poor prognosis associated with this entity. A targeted FISH panel offers timely recognition of this entity in a clinical setting.[Table: see text]

Abstract Genomic classification has improved risk assignment of pediatric, but not adult B-lineage acute lymphoblastic leukemia (B-ALL). The international UKALLXII/ECOG-ACRIN E2993 (#NCT00002514) trial accrued 1229 adolescent/adult patients with BCR-ABL1− B-ALL (aged 14 to 65 years). Although 93% of patients achieved remission, 41% relapsed at a median of 13 months (range, 28 days to 12 years). Five-year overall survival (OS) was 42% (95% confidence interval, 39, 44). Transcriptome sequencing, gene expression profiling, cytogenetics, and fusion polymerase chain reaction enabled genomic subtyping of 282 patient samples, of which 264 were eligible for trial, accounting for 64.5% of E2993 patients. Among patients with outcome data, 29.5% with favorable outcomes (5-year OS 65% to 80%) were deemed standard risk (DUX4-rearranged [9.2%], ETV6-RUNX1/-like [2.3%], TCF3-PBX1 [6.9%], PAX5 P80R [4.1%], high-hyperdiploid [6.9%]); 50.2% had high-risk genotypes with 5-year OS of 0% to 27% (Ph-like [21.2%], KMT2A-AFF1 [12%], low-hypodiploid/near-haploid [14.3%], BCL2/MYC-rearranged [2.8%]); 20.3% had intermediate-risk genotypes with 5-year OS of 33% to 45% (PAX5alt [12.4%], ZNF384/-like [5.1%], MEF2D-rearranged [2.8%]). IKZF1 alterations occurred in 86% of Ph-like, and TP53 mutations in patients who were low-hypodiploid (54%) and BCL2/MYC-rearranged (33%) but were not independently associated with outcome. Of patients considered high risk based on presenting age and white blood cell count, 40% harbored subtype-defining genetic alterations associated with standard- or intermediate-risk outcomes. We identified distinct immunophenotypic features for DUX4-rearranged, PAX5 P80R, ZNF384-R/-like, and Ph-like genotypes. These data in a large adult B-ALL cohort treated with a non–risk-adapted approach on a single trial show the prognostic importance of genomic analyses, which may translate into future therapeutic benefits.

Abstract Introduction: Recent results from two independent patient series have shown that chromosomal rearrangements of DUSP22 (DUSP22r+) and TP63 (TP63r+) can predict outcome in ALK-negative anaplastic large cell lymphoma (ALK-ALCL) and peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) with morphologic features resembling ALK-ALCL (Parilla-Castellar E, Blood 2014; Pedersen MB, Blood 2017). While DUSP22r+ is predictive for excellent survival similar to that of ALK+ALCL after CHOP/CHOP-like therapy, the rarely occurring TP63r+ is associated with an aggressive clinical behavior and poor outcome. The largest subgroup, i.e. patients with neither ALK nor DUSP22 nor TP63 rearrangements (triple negative), show a 5 year (yr) overall survival (OS) intermediate between that of ALK-/DUSP22r+ and ALK-/TP63r+ patients. The aim of the present study was to assess the impact of upfront high-dose therapy with autologous stem cell transplant (HDT/ASCT) on outcome in adult ALCL and PTCL-NOS patients according to their ALK, DUSP22 and TP63 status. The survival results from the two published series were pooled with those of a Nordic Lymphoma Group trial, the NLG-T-01 (d'Amore et al, JCO 2012), where patients were treated with 1st line CHOEP/CHOP followed, in chemosensitive cases, by upfront HDT/ASCT. Methods: Fluorescence in situ hybridization was performed on sections of previously constructed tissue microarrays using break-apart probes for the DUSP22-IRF4 and TP63 loci and a dual-fusion probe for TBL1XR1/TP63 fusion [inv(3)(q26q28)]. Evaluation of DUSP22 and TP63 rearrangements was performed in a blinded fashion without knowledge of PTCL subtype, clinical course, or outcome. Three independent patient cohorts were included: (i) one from Mayo Clinic consisting of 31 DUSP22r-, ALK-ALCL and PTCL-NOS (triple negative: 25; TP63r+: 6); (ii) one from Denmark consisting of 93 DUSP22r-, ALK-ALCL and PTCL-NOS (triple negative: 90; TP63r+: 3); and one from the NLG-T-01 trial consisting of 46 ALK-ALCL and PTCL-NOS (triple negative: 37; TP63r+: 1; DUSP22r+: 8), leading to a total study population of 170 patients. ALK+ ALCL was not included in the analysis, since no patients with this histology entered the NLG-T-01 trial. Association of genetic subtype with OS was assessed using Kaplan-Meier curves and Cox proportional models for hazard rate ratios (HR). Significant differences were defined as P &lt;0.05. Results: The eight DUSP22r+ patients (7 ALK-ALCL and 1 PTCL-NOS) from NLG-T-01 had a 5-yr OS of 83%, (95%CI 27-97), similar to that reported for DUSP22r+ in the Mayo and Danish cohorts (90% and 80%, respectively). No lymphoma-related events were observed in this subset. The only event was a septic death due to HDT-induced cytopenias in a patient who was in complete remission (CR). Among the 162 patients with DUSP22r-, ALK-ALCL and PTCL-NOS, those consolidated with HDT/ASCT (n=47) had a significantly better outcome (5-yr OS: 45%) than those treated with induction chemotherapy alone (5-yr OS: 30%) (n=115) (P=0.01). The patients in the HDT/ASCT group were younger (P&lt;0.001) and had more advanced stage disease (P=0.002). The improvement in OS persisted when the analysis was limited to transplant eligible patients and adjusted for age and stage (HR 0.52 95%CI 29-91, P=0.023) or International Prognostic Index (IPI) groups (HR 0.49, 95%CI 20-82, P=0.006). Of the 10 TP63r+ patients found within the pooled cohort, 6 were transplant eligible. Of these, 5 were not transplanted (intention-to-treat) while one was (Nordic trial). The latter patient achieved a still ongoing long-term CR, while all others died of lymphoma progression. Conclusion: In ALK-ALCL and PTCL-NOS patients from the NLG-T-01 trial, DUSP22r+ was associated with a very good outcome, similar to that seen in DUSP22r+ patients who had not undergone upfront autologous transplant. This observation supports the impression that upfront HDT/ASCT may not be of benefit in these patients. TP63r+ predicted poor outcome in non-transplanted patients. The impact of HDT/ASCT in the TP63r+ setting could not be adequately evaluated, since only one patient from the NLG-T-01 trial cohort was found to be TP63r+. Notably, this patient was the only survivor of the TP63r+ subset. For DUSP22r-, ALK-ALCL and PTCL-NOS patients taken as one group, those who received upfront HDT/ASCT had a superior survival compared to their age- and IPI-matched non-transplanted counterparts. Disclosures Ellin: ROCHE: Consultancy, Research Funding; CTI: Consultancy. Mannisto: Roche: Honoraria, Other: Travel expence; Takeda: Honoraria, Other: Travel expence; Amgen: Other: Travel expence; Novartis: Other: Travel expence; Celgene: Other: Travel expence; Gilead: Other: Travel expence; Pfizer: Honoraria; SOBI: Honoraria. Cerhan: Janssen: Other: Scientific Advisory Board (REMICADELYM4001); Janssen: Other: Multiple Myeloma Registry Steering . Toldbod: Takeda Pharma: Honoraria.

Anaplastic large cell lymphomas (ALCLs) are broadly classified into ALK-positive and ALK-negative. ALK-negative ALCL is composed of DUSP22-rearranged, TP63-rearranged, and triple-negative cases. While lymphoid enhancer–binding factor (LEF1) plays a crucial role in T-cell maturation, limited data exist on its expression in T-cell lymphomas, including ALCL. We characterized the expression of LEF1 in ALCL by immunohistochemistry. LEF1 nuclear expression in the neoplastic cells was graded as negative (0), weak (1+), intermediate (2+), or strong (3+), with the percentage of LEF1-positive neoplastic cells recorded. A total of 45 ALCL cases were evaluated, of which 16 were DUSP22-rearranged. About 93.8% (15/16) DUSP22-rearranged cases showed strong expression of LEF1 in >75% tumor cells, compared with 3.4% (1/29) non–DUSP22-rearranged ALCL (P<0.0001). The striking association of LEF1 protein overexpression with DUPS22 rearrangement in ALCL was further confirmed by a gene expression profiling study which revealed significantly higher LEF1 expression in DUSP22-rearranged ALCL compared with other ALCL subtypes (P=0.0001). Although LEF1 is a nuclear mediator of the Wnt/β-catenin pathway, CTNNB1 RNA and protein levels were not overexpressed in LEF1-positive cases, suggesting the LEF1 overexpression in ALCL may not be involved in the Wnt/β-catenin pathway. The strong and uniform LEF1 expression pattern has a high positive predictive value (93.8%) and high negative predictive value (96%) for DUSP22 rearrangement in ALK-negative ALCL. The combination of characteristic morphologic and molecular features of DUSP22-rearranged cases with the high LEF1 expression further emphasizes that DUSP22-rearranged ALCL represents a distinct clinicopathologic subset of ALCL.

Purpose: Acute myeloid leukemia (AML) is the most common acute leukemia in adults, affecting approximately 20,000 patients annually in the United States. AML genetic subtypes, as defined by the World Health Organization (WHO), are identified through fluorescence in situ hybridization (FISH), conventional chromosome analysis, and sequencing techniques. Mate pair sequencing (MPseq) is a next generation sequencing (NGS) technology optimized to detect genome wide structural variants and copy number alterations at high resolution. Our study goal was to investigate the prognostic value of MPseq in comparison to FISH, chromosome, and sequencing studies in the evaluation of AML patients. Methods: We performed a prospective study using blood and bone marrow samples from 105 patients with a diagnosis of AML, using MPseq, along with chromosome, FISH, and NGS or PCR studies to detect small mutations. Cytogenetic and molecular genetic results were correlated with MPseq findings. We also analyzed the MPseq data for chromoplexy, chromothripsis, and progressive complexity. Junction and copy number burden, the incidence of structural variation in the genome and the percent of the genome with aberrant copy number, were evaluated. Overall survival statistics were stratified by AML subtypes and observed anomalies. Results: Although structural variants in AML were characterized at a high resolution using MPseq when compared to conventional cytogenetic methods, risk stratification using current European Leukemia Net (ELN) guidelines was not improved by MPseq. The cohorts involving 5q and/or 7q deletions exhibited high levels of genomic complexity when compared to normal karyotype AML (NK-AML). The incidence of copy number gains, losses and junctions was greatest in 5q and 7q co-deletions (5q/7q) (16.5, 25.0, 69.3) and 5q deletions (5q) (9.8, 16.7, 31.6) subtypes compared to 7q deletions (3.4, 7.0, 6.7) and NK-AML (2.6, 4.3, 3.8) (p&lt;0.001) subtypes. Chromoplexy, chromothripsis, and progressive structural complexity were detected in most samples with 5q deletions and 5q/7q co-deletions, but absent in samples with 7q or NK-AML. Biallelic inactivation of TP53 by sequencing mutation and/or deletion was common in the 5q/7q co-deletion (14/18 cases) and 5q deletion cohorts (7/10 cases), rare in the 7q deletion cohort (1/11 cases), and absent in the NK-AML (n=44) cohort. The median OS was significantly worse for patients with 5q/7q deletions (122.5 days) and 5q deletions (248 days) compared to NK-AML (413.5 days; p&lt;0.001 and p=0.017, respectively) and between 5q/7q deletions and 7q deletions (370.5 days; p&lt;0.001). No significant difference was observed between 5q/7q and 5q deletion subtypes, between NK and 7q deletion subtypes and between 5q and 7q deletion subtypes. The median OS was also significantly shorter for patients with TP53 alterations compared to patients with normal TP53 status. Patients with chromoplexy, chromothripsis and/or progressive structural complexity identified by MPseq had a significantly shorter median OS compared to patients without these features. (p&lt;0.0001) Discussion: Risk stratifications based on current guidelines using cytogenetic and sequencing results were not adjusted due to MPseq results, which is not surprising when primary abnormalities are observed by conventional cytogenetic methods. NK-AML cases did not appear to benefit from a high resolution genomic evaluation. However, MPseq added value when structural variation required additional characterization, detecting novel rearrangements, such as a KAT6A/SORBS3 fusion. Lastly, we recognized common mischaracterizations made by conventional chromosome studies - including missed TP53 deletions in 7 cases, 5q/7q deletions misinterpreted as monosomies, cryptic NUP98 rearrangements, and unappreciated genomic complexity correlating with poor OS. These mischaracterizations challenge the use of conventional chromosome studies as a gold standard without accompanying FISH or MPseq studies. MPseq, similar to other structural methodologies such as optical mapping and long read sequencing, should be considered important complements to standard cytologic techniques given the important additional genomic information obtained. The additional structural variant characterization will be critical in paving the way for genomic discovery with the overall goal of improving prognostication for patient care. Figure Disclosures Vasmatzis: WholeGenome LLC.: Other: Owner; Mayo Clinic: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Introduction: Anaplastic large cell lymphomas (ALCLs) are CD30-positive T-cell lymphomas classified into ALK-positive and ALK-negative. The ALK-negative ALCLs are a genetically heterogeneous group that includes DUSP22-rearranged, TP63-rearranged and triple-negative cases. The DUSP22-rearranged ALCLs characteristically grow in a diffuse sheet-like pattern and are composed of intermediate-sized monomorphous hallmark cells, admixed with smaller cells with prominent nuclear indentations and occasional central nuclear pseudo inclusions (King RL et al, Am J Surg Pathol. 2016). Further, DUSP22-rearranged ALCL is a molecularly distinct subset of ALCL with a unique immunogenic phenotype that portends a favorable prognosis (Luchtel RA et al. Blood 2018). Lymphoid enhancer binding factor (LEF1) is a crucial nuclear mediator of the Wnt/ β-catenin pathway and a transcription factor involved in T-cell maturation. However, limited data exists on the association of LEF1 in T-cell lymphomas, including ALCL. The aims of this study were to explore LEF1 expression by immunohistochemistry in different subsets of ALCLs and to analyze the association of Wnt/ β-catenin pathway in this cohort. Methods: After approval by the institutional review board, we screened pathology reports from January 1, 1995 to December 31, 2019 and identified patients with a diagnosis of ALCL using our institutional database. Details on fluorescence in situ hybridization studies in ALK-negative cases were documented. Immunostaining for LEF1 and β catenin was performed on all cases where formalin fixed paraffin embedded tissue was available. The presence or absence of β catenin nuclear staining was recorded. LEF1 nuclear staining in the neoplastic ALCL cells was graded as negative (0), weak (1+), intermediate (2+) or strong (3+) and the percentage of LEF1-positive neoplastic cells was detailed (Figure 1). LEF1 scoring was performed by manual counting of the stained nuclei out of all tumor nuclei by two pathologists (A.R. and M.S.) and the grading was reviewed by another pathologist (P.J.K.). Results: We evaluated 45 ALCL cases, including 41 (91.1%) ALK-negative and 4 (8.9%) ALK-positive ALCLs. Among the ALK-negative ALCLs, there were16 DUSP22-rearranged, and 25 non-DUSP22-rearanged (7 TP63-rearranged and 18 triple-negative) cases. Fifteen (94%) of 16 DUSP22-rearranged ALCLs showed strong expression of LEF1 in &gt;75% tumor cells (Figure 2). In contrast, this strong and uniform LEF1 overexpression was only detected in 1 of 29 (3%) of the remaining ALCL cases (P &lt;.0001) (Table 1). We previously characterized a distinctive molecular signature in ALK-negative ALCLs with DUSP22-rearrangements using gene expression microarray analysis on frozen ALCL tissue samples (Luchtel RA et al. Blood 2018). On examining LEF1 gene expression in this previously published dataset, DUSP22 -rearranged cases had significantly higher LEF1 expression than any other genetic subtype (triple-negative, TP63-rearranged, or ALK-positive). Overall, mean LEF1 expression was 6.3-fold higher in ALCLs with DUSP22 rearrangements than in ALCLs without DUSP22-rearrangements (P=0.0001). LEF1 is a coactivator of the Wnt/β-catenin pathway; therefore, it is reasonable to hypothesize the overexpression of LEF1 may promote Wnt/β-catenin signaling. However, all LEF1-positive cases were negative for β-catenin by immunohistochemistry, suggesting that LEF1 overexpression is independent of the Wnt/β-catenin pathway signaling in these cases. Conclusions: There is a striking association between high LEF1 expression and DUSP22-rearrangements in ALCLs. The strong and uniform LEF1 expression pattern has a high positive predictive value (94%) and high negative predictive value (96%) for DUSP22- rearrangement in ALK-negative ALCLs (Table 2). The combination of characteristic morphologic and molecular features of DUSP22-rearranged cases with the unique LEF1 expression further emphasizes that DUSP22-rearranged ALCL represents a distinct clinicopathologic subset of ALCL. Disclosures No relevant conflicts of interest to declare.