The term « double » or « triple hit lymphoma » is commonly used to describe mature B cell neoplasms with either BCL2 and/or MYC and/or BCL6 gene rearrangements. These rare and aggressive lymphomas ...with high Ki67 expression are categorized as « B-cell lymphomas unclassified, with features intermediate between diffuse B-cell lymphoma and Burkitt lymphoma » category in the WHO 2008 classification. To our knowledge, only 2 cases of lymphoma have been described with four specific genetic events (quadruple hit) involving MYC, BCL2, BCL6 and CCND1 genes (Bacher U. et al., Genes Chromosomes Cancer 2011). We describe here the third observation.
A patient, a 79 years old man, suffering from paraesthesias for 4 months, was admitted for polyneuritis in a context of poor general condition. Clinical examination showed the presence of numerous axillary, supraclavicular, mediastinal and inguinal lymphadenopathy, neuro-meningeal invasion and skin infiltration. The biopsy of a skin nodule of left arm revealed an infiltration consisting in large proliferating cells (Ki67 80%) stained by anti-CD20, BCL2 and BCL6 antibodies, but not with CD10 nor CD23, consistent with a diffuse large B-cell lymphoma (DLBCL), NOS diagnosis. Blood cell count showed 8.1 G/L leukocytes, 13.2 g/dL hemoglobin, 166 G/L platelets. LDH and β-2 microglobulin were elevated (989 U/I, and 9.14 mg/L respectively). Blood cell film examination showed the presence of 28% of pathological basophil lymphocytes (medium sized, with slightly clumped chromatin and frequent prominent nucleoli). Flow cytometry revealed that these cells expressed a monotypic lambda immunoglobulin light chain and were CD19, CD20, FMC7, CD22 positive, with a dim CD5 positivity and no CD10 staining. The negativity of CD23 associated to strong CD148 staining (Miguet et al, J Proteome Res2009) were in favour of the diagnosis of variant pleomorphic mantle cell lymphoma (MCL).
Cytogenetic study performed in the WBC found a complex hyperdiploid karyotype (47 chromosomes) with a t(3;22) translocation involving BCL6 and IGL genes, structural abnormality of a chromosome 8 resulting in juxtaposition of 5’MYC and BCL2 in FISH (with break of the MYC probe in FISH), a derivative chromosome 18 from a t(14;18) translocation with fusion of 5’IGH and BCL2, and a t(11;14) complex translocation involving IGH and CCND1 (54% of the nuclei). Overexpression of cyclin D1 was detected in the WBC by RQ-PCR, as well as in the skin lesion using immunochemistry. Others numeral (trisomy 12) and structural abnormalities (involving the 1, 7, 14 and 21 chromosomes) were also detected.
The patient was treated with a chemotherapy combining rituximab, ifosfamide, cytosine arabinoside and intrathecal methotrexate. He is still alive 5 months after the diagnosis.
This third case of quadruple hit lymphoma confirms the complexity of the classification of such aggressive malignancies. Initial rearrangement of the CCND1 gene characterizes MCL that may harbour in very rare cases additional rearrangements of MYC or BCL6. Conversely, cyclin D1 overexpression is considered a rare feature in DLBCL. Recently, Ok CY et al. (Cancer 2014) proposed to reclassify DLBCL with expression of cyclin D1 and CCND1 chromosomal rearrangement and CD5 positivity as aggressive pleomorphic MCL variant. But no case with rearrangement of 2 (or more) genes (BCL2 and/or MYC and/or BCL6) was described in this study.
Juskevicius D et al. (Am J Surg Pathol 2014) suggest the existence of a “gray zone” in which morphologic, clinical and genetic features are insufficient to segregate CD5- and SOX11-negative lymphomas with overexpression of cyclin D1/ translocation involving CCND1between blastoid MCL from cyclin D1-positive DLBCL.
In our case, immunophenotyping of circulating cells (CD5+, CD148++) as well as genetic and molecular features (translocation involving CCND1 and IGH, and overexpression of cyclin D1) allow us to diagnose a probable genetically unstable aggressive pleomorphic MCL variant with rearrangement of several extra genetic hits.
No relevant conflicts of interest to declare.
Abstract 4890
Gene amplification is a mechanism whereby a tumor cell can increase the copy number of specific gene sequences and gain a proliferative advantage. Although amplifications are common in ...solid tumors, they are relatively rare in hematological neoplasms. We report here on a patient with an acute erythroid leukemia and a jumping translocation of a hsr(11q) in a complex karyotype, without MLL amplification.
The patient was 40 years old when he was admitted for asthenia, peripheral blood showing pancytopenia (Hb=111G/L; neutrophils= 0.23 G/L; platelets 92 G/L), without circulating blast cells. Bone marrow was hypercellular with the presence of more than 50% of erythroid precursors and more than 20% of myeloid blast cells in non-erythroid cell population, leading to the diagnosis of erythroblastic acute leukemia. A marked dysgranulopoiesis was also detected.
Conventional cytogenetics showed a complex karyotype with a del(5q), a unbalanced t(7;17) leading to partial 7q deletion and homogeneously staining regions (hsr). Fluorescence in situ hybridization confirmed the del(5q), and showed that TP53 was not deleted in the t(7;17). Multi-FISH (M-FISH) pointed out that the hsr consisted of chromosome 11 and was implicated in 3 different translocations with 3 different partner chromosomes in 3 different clones. To further characterize the amplicon and determine which bands were implicated, we used a chromosome 11 m-band probe. It revealed that the bands implicated are the same on the der(3), der(12) and der(20) and are localized between 11q23.3 and 11q25. A series of BAC probes showed that different genes, present in these regions, were amplified: ETS1, FLI1, KCNJ5, NFRKB, SNX19, HNT, OPCM, but not MLL.
Amplifications of chromosome 11q usually includes MLL, but more telomeric amplicons have also been reported in AML and myelodysplatic syndromes (MDS). A very close 11q amplification was identified in 3 AML/MDS cases (Crossen et al, 1999; Tyybäkinoja et al, 2006). Also, the ETS1 oncogene was found to be rearranged and 30-fold amplified in a case of acute myelomonocytic leukaemia, in which an hsr occurred on 11q23 (Rovigatti et al, 1986).
The role of chromosomal amplifications in leukemia is unclear, but it has been suggested that they are associated with rapid disease progression and short survival. Jumping translocations are an unusual phenomenon and have been rarely reported in hematological malignancies. Whether jumping translocations play a role in tumor genesis or confer a selective growth advantage on tumor cells is unknown. The combination of hsr and jumping translocations as described here are very rare in hematological malignancies. The cases of the literature (Yoshida et al, 1999) and the one presented here suggest that the 11q24-q25 region may harbor new candidate oncogenes, together with unusual chromosomal mechanisms.
No relevant conflicts of interest to declare.
TET1 genomic breakpoints and clinical features of MLL-TET1 rearrangements have been described in 13 acute leukemia cases, 11 in AML, 2 in B cell-precursor ALL. The incidence of this rare ...translocation was evaluated to 0.3% of MLL rearranged AML cases (5 out of 1590 MLL Meyer C. Leukemia 2013). Although those cases are very uncommon, their study can improve our current understanding of leukemogenesis. We report here the first t(10;11) MLL-TET1 positive case of lymphoblastic T lymphoma occurring in a 31 years old male patient, with a subsequent transformation to AML.
The patient was referred for a large mediastinal mass and right pleural effusion. Mediastinal and bronchus biopsies led to the diagnosis of a precursor-T cell lymphoblastic lymphoma, expressing CD3, CD5, CD4, CD8, CD10 antigens, without any expression of CD34 or CD79.
Molecular analyses of the malignant T-cells showed a clonal TCR gamma-chain gene rearrangement together with HOXA10 overexpression. FISH analysis showed a MLL breakage. The partner gene, TET1, was identified using RP11-9E13 and RP11-314J18 BACs, corresponding to the recurrent translocation t(10;11)(q22;q23). MLL-TET1 fusion transcript was detected (intron 8 of TET1 fused to exon 8 of MLL), as well as its reciprocal transcript.
The patient was treated following the (GELA) LL03 protocol, and was considered in complete remission after induction and consolidation phases. Fourteen months after the diagnosis, a bone marrow examination was performed for thrombopenia (6 G/L) which revealed a myelomonocytic acute leukemia with trilineage dysplasia.
At this time, The MLL-TET1 fusion transcript as well as HOXA10 overexpression was still present but the TCR rearrangement was not detected. A non-familial donor allogeneic bone marrow transplant was performed in CR after intensive chemotherapy, that was complicated by a grade IV acute graft-versus-host disease. The patient died 54 days after the transplant of bacterial sepsis leading to multi-organ failure.
MLL-TET1 fusions have been described in 13 cases in the literature, mainly in AMLs (11/13 cases, mostly AML M4 or M5 cases) and in B-ALLs (2/13 cases). The case reported here presents two interesting features. Firstly, this patient harbors the first MLL-TET1 fusion reported to date in T-ALL, and secondly this case presented a lymphoid to myeloid phenotype switch during the time course of the disease.
This strongly suggests that the translocation occurred very early during hematopoietic differentiation, prior to the lymphoid/myeloid commitment. As described for the Ph1 chromosome rearrangement, the t(10;11) translocation may arise in hematopoietic stem cell rather than in committed progenitors. These features are also described in 8p11 stem cell syndrome that involves FGFR1. In both cases, genetic rearrangements arise in myeloid or lymphoid neoplasms with possible subsequent transformation.
TET family enzymes convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and play a key role in active DNA demethylation. TET1 and TET2 are also the key enzymes responsible for the presence of 5hmC in mouse embryonic stem cells (ESCs) (Koh KP., Cell Stem Cell 2011), and TET1 functions to regulate the lineage differentiation potential of ESCs. In addition to its role in DNA demethylation, TET1 interacts physically with NANOG and NANOG/TET1 co-occupy genomic loci of genes associated with both maintenance of pluripotency and lineage commitment in embryonic stem cells (Costa Y., Nature 2013). Taken together, these observations enlighten possible mechanism of the lineage switch observed in this case, and may be a rationale for using demethylating agents in MLL-TET1 neoplasms.
No relevant conflicts of interest to declare.
The ETV6/GOT1 fusion, resulting from t(10;12) (q24;p13), has been recently described in a myelodysplastic syndrome. We reported a second case of t(10;12)-positive myelodysplastic syndrome in whom ...fluorescent in situ hybridization confirmed the non-random translocation but molecular biology analyses revealed a ETV6/GOT1 chimera varying from the first case described.
Deletions of the long arm of chromosome 14 are rare (<5%) but recurrently observed in mature B-cell neoplasms, particularly in CLL. The size of the deletions is variable, and the molecular ...consequences are unknown. The aim of our study is to characterize this abnormality in a large cohort of patients.
The Groupe Francophone de Cytogenetique Hematologique (GFCH) collected data from 89 patients with CLL or Small Lymphocytic Lymphoma (SLL), harboring a del14q. Morphological review was performed for 65 of them and immunological review for 48. All karyotypes were reviewed by members of the GFCH. Fluorescence in situ hybridization (FISH) analysis was performed with CEP12, 13q14, TP53, ATM, 6q21, and IGH probes, and BACs RP11-35D12 and RP11-226F19 covering the ZFP36L1 gene on 14q24.1. SNP-array analysis (illumina omni1, omin2.5) was performed for 37 patients. The IGHV status was analyzed locally, or in our laboratory. The mutation hotspots of NOTCH1 (exon 34), SF3B1 (exons 14-16), XPO1 (exons 14-15), MYD88 (exon 5) and TP53 (exons 4-10) were analyzed by direct sequencing.
Patients were classified as 49 CLL Matutes score 4-5, 5 atypical CLL score 3 (all CD5+, CD23+), and 27 SLL. Eight patients were excluded with a Matutes score<3 or not evaluable. The sex ratio M/F was 1.02, the median age at diagnosis was 64.5 years 29-87. Regarding all CLL, there were 35 (66%) stages A, 10 (19%) stages B and 8 (15%) stages C. The median time between diagnosis and the first treatment (TTT) was 17 months 0-144, the overall survival (OS) at 5 years was 93.7%. For the 27 SLL patients, the median TTT was 1 month 0-85, and the OS at 5 years was 88.1%.
The karyotype showed chromosomal translocation in 26/79 (33%) (10 balanced, 16 unbalanced) and was complex (> 3 abnormalities) in 26/79 (33%) cases. Using karyotype and FISH, we observed 28/79 (35%) trisomy 12, 12/79 (15%) 13q14 deletions, 11/80 (14%) TP53 deletions, 5/79 (6%) ATM deletions, 3/76 (4%) 6q21 deletions. The whole CLL cohort showed 15/53 (28%) tri 12, 11/53 (21%) del13q, 8/54 (15%) delTP53, 4/53 (7%) delATM, 2/50 (4%) del6q.
IGHV status was not mutated in 41/53 (77%) patients, and the gene IGHV1-69 was rearranged in 21/52 (40%) cases. NOTCH1 gene was mutated in 14/45 (31%) patients, SF3B1 in 2/45 (4%), XPO1 in 2/45 (4%), MYD88 in 0/43, TP53 in 6/43 (14%) cases. A significant association was observed between TP53 disrupted and NOTCH1 mutations (p=.04). NOTCH1 mutation was not correlated with tri12.
Regarding all the cytogenetic and molecular data, there was no significant difference between CLL score 4-5 and CLL score 3, and between CLL and SLL.
Compared with common CLL in the literature, CLL with del14q dysplayed more tri12 (p<.03) and NOTCH1 mutations (p<.003), less del13q (p<.0006), more unmutated IGHV (p<.00001) and V1-69 repertoire (p<.00001). Compared with common SLL in the literature, SLL with del14q also exhibited more tri12, unmutated IGHV (p<.01) and V1-69 (p<.04).
The 14q deletions appeared distributed along chromosome 14 from bands q11 to q32. The centromeric and telomeric breakpoints of the 14q deletion were investigated by FISH or SNP-array when material was available, and allowed us to identify a main group (Group 1) among 4 groups: Group 1: 37/77 (48%) patients, with IGH and ZFP36L1 loci rearranged; Group 2: 17/77 (22%), with ZFP36L1 deleted and IGH not deleted; Group 3: 7/77 (9%), with ZFP36L1 and IGH not deleted; Group 4, 16/77 (21%), all the other combinations. Group 1 showed a deletion del14q24.1-14q32.3 of about 38 megabases, which broke in or near ZFP36L1, and in the IGH gene. It included 26 (70%) CLL score 4-5 and 11 (30%) SLL. When compared to the other groups, Group 1 showed significantly more tri12 (p=.004), and NOTCH1 mutations (p=.02). IGHV status was unmutated in 22/24 (92%) patients in Group 1, 12/24 (50%) harboring the gene V1-69.
In conclusion, the size of the 14q deletion is variable, with in about half of the cases a recurrent interstitial deletion 14q24.1-14q32.3. Both CLL and SLL with del14q, particularly with the 14q24.1-14q32.3 deletion, are associated with poor prognosis parameters, like short time to treatment, trisomy 12, NOTCH1 mutated, and unmutated IGHV status, with an overrepresentation of the V1-69 gene.
No relevant conflicts of interest to declare.
Conventional cytogenetics (CC) of B-cell lymphoproliferations remains difficult because of low mitotic in vitro activity of the leukemic cells. Therefore, mitogen stimulation of B-cells is required ...to analyze an adequate number of metaphases. Chromosome abnormalities using CC with TPA can be detected in up to 50% of chronic lymphocytic leukemia (CLL), but the development of FISH techniques has allowed the detection of selected chromosome abnormalities in more than 80% of CLL. However, FISH is restricted, since information is only available for the genes/loci for which probes are used. So, for a comprehensive genetic analysis, CC is essential because it provides an overview of all microscopically visible chromosome abnormalities important as prognostic factors. The use of the immunostimulatory CpG-oligonucleotide DSP30 to effectively induce cell cycle progression of CLL cells in vitro has been reported. This proliferation is markedly enhanced upon addition of Interleukine-2 to cultures. To our knowledge and to date, there has been no direct comparison of classical TPA versus DSP30+IL-2. DSP30+IL-2 stimulation has been successfully tested in CLL but no data are available for other lymphoproliferations. We cultured 132 B-cell lymphoproliferations (80 CLL and 52 other B-cell lymphoid neoplasms (BCLN)) in parallel, in presence of TPA or DSP30+IL-2. The objective of this study was to evaluate the suitability of DSP30+IL-2 as a routine B-cell mitogen for metaphase cytogenetics. CC successfully analyzed 94.9% of CLL and 98.1% of BCNL with more than 80% abnormal karyotypes. For CLL, failures of karyotypes were more frequent in cultures with DSP30+IL-2 (14%) than in those with TPA (4%). The rate of failures were similar for BCLN (6% versus 4%). For CLL, there were significantly fewer metaphases in DSP30+IL-2 than in TPA spreads (mean of 50 versus 72 metaphases per slide respectively, p=0.0007), as well as for BCLN (mean of 50 versus 71 metaphases per slide respectively, p=0.009). However, the proportion of abnormal metaphases was significantly higher in DSP30+IL-2 (mean of 59%) compared to TPA cultures (mean of 26%, p=0.00265) for CLL and for BCLN (mean of 57% versus 33%, p=0.0065). Stimulation with DSP30+IL-2 allowed to detect more abnormalities, more abnormal subclones and more complex karyotypes in CLL and in the majority of BCLN. Though FISH exploration using a large probe panel has yielded valuable results in lymphoproliferative diseases, it underestimates the heterogeneity of chromosomal aberrations. Complexity of chromosomal changes, recently associated to unfavorable outcomes, can only be assessed with CC. In conclusion, our results in both CLL and BCLN indicate that the immunostimulatory oligonucleotide DSP30 in combination with IL-2 is an easy and efficient stimulus in metaphase generation for routine chromosomal banding.
The RUNX1 gene is implicated in numerous chromosomal translocations that occur in acute myeloid leukemia (AML) and result in chimeric genes. In this study, 397 consecutive AML cases were analyzed ...using RUNX1 fluorescence in situ hybridization (FISH) probes. Three cases of the recently described translocation, t(7;21)(p22;q22), were identified, which expressed RUNX1-USP42 (ubiquitin-specific protease 42) fusion transcripts, associated with 5q abnormalities and hyperploidy. These cases displayed homogeneous morphological features (including phagocytosis) and aberrantly expressed CD56 and CD7 lymphoid antigens. Although very few data are available from previously reported cases, when these features are present, a detailed chromosomal analysis, including hybridization with RUNX1 FISH probes, should be performed at diagnosis to recognize chromosomal abnormalities. Additional cases of t(7;21) positive AML should be evaluated to characterize this potentially rare AML entity in greater detail.
The nucleoporin gene NUP98 is known to be rearranged in several recurrent translocations occurring in de novo and therapy-related myelodysplastic syndrome and acute leukemia, in children or adults. ...All these abnormalities seem to have bad prognosis, thus, it is important to identify NUP98 rearrangements. As other genes (MLL, ETV6, RUNX1, ...), NUP98 may fuse to different partners, often homeobox genes such as HOXA, HOXC, HOXD, PMX1, but also non homeobox genes such as RAP1GSD1, NSD1, NSD3, LEDGF, ADD3, DDX10, and TOP1. The fusion transcript always juxtapose the N-terminal FG repeats of NUP98, required for its docking function, to the C-terminus of the partner gene, which contains the homeodomain in the case of a homeobox partner gene. We identified a t(9;11)(q34.1;p15.5) by conventional cytogenetic analysis, in a 65 years old Caucasian female who developed a t-AML four years after lymphoma treatment. The involvement of NUP98 gene was confirmed by FISH analysis using BAC RP11-120E20 and PAC RP11-1173K1. 3′RACE analysis allowed to identified a novel partner gene, the class II homeobox gene PRRX2 (Paired Related homeobox 2), located on 9q34. The breakpoint occurred in an infrequent breaking region in exon 11 of NUP98, and in exon 2 of PRRX2. The NUP98-PRRX2 fusion transcript was cloned and sequenced, and confirmed by RT-PCR. As its homologue PRRX1 (PMX1), PRRX2 is a DNA-binding transcription factor that is essential for fetal development. PRRX1 has been described to be fused with NUP98 in t(1;11)(q23;p15), but it is the first time PRRX2 is implicated in leukemia, and even in malignancy. Further studies are necessary to confirm the recurrence of this translocation and its prognosis. Furthermore, transformation assays in cells lines and transgenic mice studies would be interesting to understand the leukemogenicity induced by the NUP98-PRRX2 fusion transcript.
Abstract Polycythemia vera (PV) is a clonal stem cell disorder characterized by an excessive erythrocyte production. At diagnosis, a normal karyotype is found in ≤80% of cases, but an abnormal ...karyotype frequently develops with evolution. Trisomy 9 and gains on 9p are some of the most frequent cytogenetic abnormalities, together with trisomy 8 and del(20q) in both PV and idiopathic myelofibrosis. We report the case of a 54-year-old man whose disease was classified as an acute myeloid transformation of PV. Cytogenetic and multicolor fluorescence in situ hybridization (FISH) analysis detected several chromosomal abnormalities that included an amplification of 9p. Complementary FISH analysis established amplification of the 9p22∼p24.3 region including several known genes: MLLT3 (alias AF9 ), JMJD2C (alias GASC1 ), JAK2 , and SMARCA2 (alias BRM ). JAK2V617F mutation status was quantitatively assessed by allele-specific quantitative polymerase chain reaction. Although crossing points analysis showed JAK2V617F mutated alleles at 52%, it is still impossible to describe conclusively the mutational status of the amplified JAK2 gene within the sole homogeneously staining region, because total genomic DNA was extracted for the analysis and not only DNA from cells with the homogeneously staining region. Gains on 9p being among the most common anomalies in PV, amplification of a gene or genes on this region may play a crucial role in the pathogenesis or evolution of PV.
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