1771 Introduction: Deletion of the long arm of chromosome 11 (11q22-q23) is one of the most common chromosome aberrations (∼12%) in CLL and is associated with rapid disease progression and shorter overall survival (OS). The commonly deleted region contains the genes ATM and BIRC3. ATM (chromosome 11q22.3) plays a central role in activating TP53, DNA recombination processes, and cell cycle control. ATMmut were described to occur in ∼35% of CLL patients with 11q deletions. The apoptosis inhibitor BIRC3 is located on chromosome band 11q22.2, 6.0 Mb proximal of ATM. BIRC3mut have recently been described with a mutation frequency of 4% in CLL (Rossi D, Blood 2012). Aims: 1. Determine the frequency of deletions and mutations of ATM and BIRC3 in CLL with 11q deletion. 2. Analyze the association of ATM and BIRC3 mutations with ATM and BIRC3 deletions. 3. Characterization of the landscape and prognostic impact of ATM and BIRC3 mutations. Patient and Methods: The investigated cohort comprised 60 de novo CLL cases harboring del(11q) identified by chromosome banding analysis. The cohort comprised 47 males and 13 females, median age was 68.9 years. Survival data was available in 38 cases. For sensitive mutation detection of the complete coding region of ATM (3056 amino acids) and BIRC3 (604 amino acids) an amplicon deep-sequencing approach (454 Roche Life Sciences, Branford, CT) was developed. Patients were further characterized for mutation status of TP53 (n=60), SF3B1 (n=59), and IGHV (n=60). Additionally, patients were investigated by interphase FISH for ATM (n=60; MetaSystems, Altlussheim, Germany) and BIRC3 (n=39; BAC RP11–177O8, BlueGnome, Cambridge, UK) deletions. Results: Based on FISH results, all 60 cases showed an entire gene deletion of ATM. Of those cases investigated for BIRC3del, 34/39 (87.2%) cases showed a deletion, thus 5/39 (12.8%) carried an ATMdel only. Mutational screening of the ATM and BIRC3 genes identified 24 ATMmut in 19/60 (31.7%) patients and 3 BIRC3mut in 3/60 (5.0%) cases. Additional mutations were detected in TP53 (3/58; 5.2%), and the spliceosome machinery gene SF3B1 (10/59, 16.9%). 49/60 (81.7%) cases were IGHV unmutated, whereas 11/60 (18.3%) cases were IGHV mutated. The majority of ATMmut were found to be missense mutations (n=15) followed by nonsense (n=4), frame-shift (n=4), and in-frame (n=1) variants. In more detail, only one mutation occurred in two distinct patients (p.Ile2888Thr). Most cases showed only one mutation (n=15, 78.9%), whereas 3 cases (15.8%) showed two and one case (5.3%) three mutations. Mutations were spread across the entire coding region (exon 3–59). The median mutational burden as assessed by deep-sequencing read counts was 38.5%, ranging from 4.0–89.5%. For BIRC3 3 deletions (1–4 bp) were observed resulting in 2 frame-shift and 1 splice-site mutation. The median mutation load was 32.5% (range: 20.0%-92.0%). In addition, two cases with BIRC3mut showed also a BIRC3del (n=1 data not available). Interestingly, all of these 3 cases with BIRC3mut were wild-type in the ATM gene. To further address the role of ATMmut association analyses with respect to age, gender, white blood cell count, haemoglobin level, and platelet count were performed, however, no correlations were observed. Further, ATMmut were not correlated with IGHV (3/11 vs 16/49, P=1.00), TP53 (0/3 vs 19/55, P=0.544) or SF3B1 (3/10 vs 15/49, P=1.00) mutation status. However, the presence of ATMmut in CLL with del(11q) was associated with shorter OS (76.2% vs 95.0% at 3 years), although this difference was not significant. However, when comparing OS of ATMmut cases to cases without del(11q) (n=1,245) we detected a trend towards a shorter OS (76.2% vs 94.2% at 3 years, P=0.149) in contrast to cases with del(11q), but without ATMmut in comparison to cases with no del(11q) (95.0% vs 94.2%, P=0.731). Conclusions: 1. BIRC3 was mutated in only 5.0%, whereas ATM was mutated in 31.7% of patients with del(11q). 2. No mutation hotspot regions were observed, thus analyses of the whole genes are mandatory. 3. ATMmut were associated with a trend to shorter OS in CLL with del(11q). In comparison to cases without del(11q), cases with ATMmut showed shorter OS, indicating a more relevant role of ATMmut on prognosis versus cases with a del(11q) only. 4. In 38 cases (63.3%) with del(11q) neither ATM nor BIRC3 mutations were detected suggesting that further genomic alterations which are not yet identified play a role in CLL with del(11q). Disclosures: Grossmann: MLL Munich Leukemia Laboratory: Employment. Kohlmann:MLL Munich Leukemia Laboratory: Employment. Schnittger:MLL Munich Leukemia Laboratory: Equity Ownership. Weissmann:MLL Munich Leukemia Laboratory: Employment. Jeromin:MLL Munich Leukemia Laboratory: Employment. Kienast:MLL Munich Leukemia Laboratory: Employment. Kern:MLL Munich Leukemia Laboratory: Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Equity Ownership.
Introduction In 2012, whole-genome, whole-exome and global transcriptome sequencing studies unraveled the molecular complexity of Burkitt lymphoma (BL). Amongst a set of up to 70 recurrently mutated genes (Love C. et al., Nat. Genet. 2012), essential affected oncogenic pathways were discovered including mutations in MYC and the transcription factor TCF3 (Schmitz R. et al., Nature 2012), as well as inactivating mutations of ID3 (Richter J. et al., Nat. Genet. 2012). Aims (1) To validate the mutation frequency and mutational landscape of selected candidate target genes (ID3, MYC, TCF3, and TP53) in an independent cohort of 60 adult patients with Burkitt Lymphoma/Leukemia. (2) To investigate the clonal composition and associations with BCL2 rearrangements using a quantitative next-generation sequencing assay. Methods The patient cohort included 33 cases with Burkitt Leukemia (33/60, 55.0%) and 27 cases with Burkitt Lymphoma (27/60, 45.0%). 36 (60.0%) of these were single-hit lymphomas only harboring MYC-rearrangements, whereas 24 (40.0%) cases were multiple-hit lymphomas harboring in addition at least one of the following gene rearrangements: BCL2, BCL6, and/or CCND1. The median age was 60.8 years (range 5.5 - 82.7). All cases were comprehensively characterized by cytomorphology, cytogenetics and FISH, including evaluation for MYC-, BCL2-, BCL6-, and CCND1-rearrangements. Four candidate genes were sequenced using a quantitative deep-sequencing NGS assay (median coverage of 633 reads per mutation). The lower limit of detection of mutations was set at 2%. Amplicon sequencing libraries were prepared using genomic DNA extracted from mononuclear cells. The following regions were investigated: ID3 (exons 1-2), MYC (exons 2-3), TCF3 (exons 18), and TP53 (exons 4-11), respectively. Results In total, 112 mutations were detected in 39/60 (56.5%) patients. 9/112 (8.0%) were detected with a clone size of <10%. In 17 patients with single mutations, either MYC (n=7) or TP53 was detected mutated (n=10). Double mutations were seen in 15 cases and six cases harbored three and one case four gene mutations, respectively. Interestingly, all patients with ID3 mutations harbored additional mutations. In detail, 27 ID3 mutations were observed in 14/60 (40.0%) cases. These mutations included 17 missense, 6 nonsense, 1 deletion, 2 splice-site and one frame-shift events. Eight of the 14 ID3 mutated patients harbored two or more concomitant ID3 mutations. The mutations clustered around hotspot codons p.Leu64Phe (9/27) or p.Gln81* (4/27). Of the double-mutated cases 7/8 patients harbored at least one mutation in the hotspot region. Of note, 23/27 mutations were located within the helix-loop-helix domain. MYC, the predominantly recognized oncogene in BL, was mutated in 26/60 (43.3%) of cases and in total 50 distinct mutations were discovered, including 46 missense, 2 deletions, one splice-site, and one indel events. A high number of 9 (34.6%) patients harbored two or more MYC mutations. The mutations clustered around a recurrent codon p.His374 (4/60). TCF3 mutations were detected in 2/60 (3.3%) of cases, both of them also mutated in MYC and TP53. Finally, 33 TP53 mutations were found in 27/60 (45.0%) patients. Six patients harbored two mutations (with quite different clone sizes in two of the six cases). Furthermore, we observed a positive correlation for ID3 and MYC mutations (11/14 (78.6%) ID3 mutated cases harbored MYC mutations vs. 15/46 (32.6%); p=0.004). Further, we studied correlations of the type of lymphoma (single-hit vs. multiple-hit) and found ID3 mutations positively correlated with single-hit lymphoma (13/36 (36.1%) vs. 1/24 (4.2%) cases within multiple-hit patients; p=0.005). Next, we studied correlations with BCL2 rearrangements, which were present in 20/60 (33.3%) cases. Cases with BCL2 rearrangements were associated with significantly lower mutation frequencies in TP53 (5/20 (25.0%) vs. 22/40 (55.0%), p=0.032) and ID3 (1/20 (5.0%) vs. 13/40 (32.5%), p=0.023). Finally, within our cohort of 60 lymphomas, 11 (18.3%) patients presented as single-hit lymphoma and without any of the mentioned molecular mutations. Conclusion In this independent validation study we can confirm the high frequency of mutations in ID3, MYC, TCF3 and TP53 in adult BL. As our understanding of the genetic landscape is further increased novel therapeutic approaches seem possible in this disease. Disclosures: Kohlmann: MLL Munich Leukemia Laboratory: Employment. Roller:MLL Munich Leukemia Laboratory: Employment. Kienast:MLL Munich Leukemia Laboratory: Employment. Denzel:MLL Munich Leukemia Laboratory: Employment. Grossmann:MLL Munich Leukemia Laboratory: Employment. Nadarajah:MLL Munich Leukemia Laboratory: Employment. Alpermann:MLL Munich Leukemia Laboratory: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Schnittger:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.
Background MYC translocations are observed in a variety of mature B-cell neoplasms and are also found in ALL. A clear assignment to an entity is not always possible in terms of immunophenotyping and morphology alone. So far, neither cytogenetics nor molecular genetics have been used to classify this group of diseases. Aims Analyze cytogenetic aberrations and molecular mutations in a large cohort of patients with B-cell neoplasms and MYC rearrangements to evaluate their respective value for classification. Patients and Methods 155 patients with B-cell neoplasms harboring a MYC translocation were included in this study. Chromosome banding analysis, FISH verifying the MYC rearrangement and mutation screening of the genes ID3, MYC, TP53 and SF3B1 (only in CLL) was performed. Results The cohort comprised 103 (66.5%) males and 52 (33.5%) females with a median age of 66.2 yrs (range: 5.5-87.1 yrs). Cytomorphologic and flow cytometric findings were heterogeneous with patients presenting as ALL (n=33, 21.3%), Burkitt lymphoma (n=29, 18.7%), CLL (n=29, 18.7%), and other mature B-cell neoplasms including follicular lymphoma, mantle cell lymphoma and PLL (n=64, 41.3%). MYC translocations occurred either as a single translocation event (“single hit”) or in addition to one, two or three other translocations involving BCL2, BCL6 and/or CCND1 (“double hit”, “triple hit” and “quadruple hit”, respectively (combined: “multiple hit”). Accordingly, the cohort was subdivided into 98/155 (63.2%) patients with single hit and 57/155 (36.8%) patients with multiple hit lymphoma (double hit: 39 (25.2%), triple hit: 16 (10.3%) and quadruple hit: 2 (1.3%)). Results of mutation analysis are depicted in the figure. TP53 mutations were identified in 57/155 (36.8%) patients and were significantly more frequent in Burkitt lymphoma compared to all other entities (18/29 (62.1%) vs. 39/126 (31.0%), p=0.003). MYC mutations were identified with a frequency of 48/155 (31.0%), without significant differences between entities. However, in patients with CLL we observed a slightly lower frequency than in all other entities (17.2% vs 34.1%, p=0.117). ID3 mutations were found in 20/155 (12.9%) cases and were significantly more frequent in Burkitt lymphoma compared to all other entities (10/29 (34.5%) vs. 10/126 (7.9%), p=0.001). Remarkably, in the subgroup of patients presenting as CLL no ID3 mutation was detected (0/29). Single hit lymphoma showed higher mutation frequencies of TP53 and ID3 compared to multiple hit lymphoma (TP53mut: 45.9% vs. 21.1%, p=0.002, ID3mut: 19.4% vs. 1.8%, p=0.001). In contrast, in single hit lymphoma the number of cytogenetic abnormalities observed in addition to MYC-translocation (ACA) was lower than in multiple hit lymphoma (mean: 3.5 vs. 8.5, p<0.001). Accordingly, cases with BCL2 rearrangements were associated with significantly lower mutation frequencies in TP53 (18.6% vs. 43.8%, p=0.005). Of note, single hit Burkitt lymphoma were characterized by significantly higher mutation frequencies of TP53, MYC and ID3 compared to Burkitt lymphoma with multiple hit (75% vs. 33.3%, p=0.048, 60% vs 11.1%, p=0.020; 50% vs 0%, p=0.011). CLL patients were additionally analyzed for mutations in SF3B1. Interestingly, this subgroup showed a higher frequency of SF3B1 mutations compared to published data (Cazzola et al. Blood 2013,121:260-9) (11/29; 37.9% vs. 5-17%). Conclusions 1. Mutations in ID3 and TP53 were most frequently observed in cases presenting as Burkitt lymphoma and especially associated with single hit lymphoma. 2. CLL patients with MYC translocation showed a specific mutation pattern with no ID3 mutations, a low frequency of MYC mutations, but a very high frequency of SF3B1 mutations. Further, MYC translocated CLL is characterized by a low frequency of additional chromosome abnormalities and presents predominantly as single hit lymphoma. 3. Thus far, B-cell neoplasms are mainly classified based on morphological criteria and the immunophenotype. Our data suggest that the cytogenetic and molecular genetic profile might help to establish an improved classification system. The differentiation between single hit lymphoma and multiple hit lymphoma as well as the separation of the category of CLL with MYC-rearrangements is anticipated to be clinically relevant and should be further studied. Disclosures: Denzel: MLL Munich Leukemia Laboratory: Employment. Kohlmann:MLL Munich Leukemia Laboratory: Employment. Roller:MLL Munich Leukemia Laboratory: Employment. Jeromin:MLL Munich Leukemia Laboratory: Employment. Alpermann:MLL Munich Leukemia Laboratory: Employment. Kienast:MLL Munich Leukemia Laboratory: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Schnittger:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.