MLL rearrangement with t(6;11)(q15;q23) as a sole abnormality in a patient with de novo acute myeloid leukemia: conventional cytogenetics, FISH, and multicolor FISH analyses for detection of rare MLL-related chromosome abnormalities

We report a rare case of acute myeloid leukemia (AML) with t(6;11)(q15;q23) in a 50-year-old female showing a poor prognosis. Bone marrow biopsy revealed markedly hypercellular marrow with infiltrates of myeloblasts, consistent with AML-M2 morphology. The karyotype of this patient was 46,XX,t(6;11)(q15;q23) in all analyzed cells, and the results of fluorescence in situ hybridization (FISH) and multi-color FISH analysis confirmed this unique MLL rearrangement as a sole abnormality. To our knowledge, t(6;11)(q13 approximately q15;q23) is the most rare type of MLL rearrangement involving the long arm of chromosome 6. Only two cases with t(6;11)(q13;q23) and three cases with t(6;11)(q15;q23) have been reported, but detailed clinical or laboratory data were not available. From this report, it is apparent that in a cytogenetic laboratory, the accurate detection of a rare type of MLL rearrangement is very important in the differential diagnosis, prompt treatment, and prediction of prognosis of leukemias.     

Amplification of the 11q23 region in acute myeloid leukemia.

Cytogenetic abnormalities involving the 11q23 region are found in both acute lymphoblastic leukemia (ALL) and myeloid leukemia (AML). Molecular consequences of 11q23 translocations are the formation of chimeric genes, all of them involving the MLL (mixed-lineage leukemia) gene. To evaluate the usefulness of fluorescence in situ hybridization (FISH) in detecting MLL rearrangements in AML, we analyzed 181 patients with an MLL-specific probe. Among them, we detected three patients with multiple FISH signals, reflecting genomic amplification of this chromosomal region. Extra copies of MLL have been reported previously in four patients, but did not correspond to a true gene amplification. For the first time, we describe genomic amplification of the 11q23 region (up to more than 50 copies) in AML patients. This genomic amplification could affect MLL, but other genes in the vicinity could also be the primary target. Genes Chromosomes Cancer 26:166-170, 1999.     

Granulocytic sarcomas in body cavities in childhood acute myeloid leukemias with 11q23/MLL rearrangements

Three childhood acute monoblastic leukemias (AML M5) with granulocytic sarcomas (GSs) are described. All displayed 11q23/MLL abnormalities, t(9;11)(p22;q23) in two cases and t(11;17)(q23;q21) in one case, constituting around 20% of all 11q23-positive AML cytogenetically investigated in our department. Two of the patients had GS in multiple locations, and all three had abdominal GS. In two of them, t(9;11)-positive GS was diagnosed prior to the diagnosis of AML. Fourteen (1.9%) of 752 published AML cases with 11q23 aberrations have had GS, either as a presenting feature or during disease progression. The incidence of GS has varied significantly (P < 0.05) between children (3.8%) and adults (0.8%). The most common AML subtype has been AML M5 ( approximately 75%) and the most frequent GS sites have been the skin, abdomen, orbit, and thorax. Considering the possibility of underreporting of GS in published cases and the relatively high frequency in our own series, we believe that 11q23/MLL rearrangements may predispose to GS development. Although extramedullary infiltrates in the skin are known to be frequent in cases of AML M5, which is often associated with 11q23 aberrations, the present findings indicate that GS in the abdomen, orbit, and thorax may also be common, especially in pediatric AML. Thus, the possibility of 11q23/MLL-positive GS should be suspected when tumors of uncertain derivation occur in these sites. Finally, the identification of 11q23/MLL abnormalities in GSs in two patients without overt AML underscores the importance of using cytogenetic and molecular genetic investigations as a diagnostic approach in the evaluation of tumorous lesions of unknown origin. Genes Chromosomes Cancer 27:136-142, 2000.     

Characterization of a t(I0; II) (pI3-I4; qI4-2I) in the monoblastic cell line U937

Previous analysis of the monoblastic cell line U937 has shown that several sublines contain a rearranged chromosome arm I I q. In order to determine the true nature of the rearrangement, fluorescence in situ hybridization (FISH) was carried out with various combinations of single copy anonymous markers, clones containing genes, a chromosome 10 paint, and an I I centromere specific sequence. The rearrangement was deduced to be a reciprocal translocation between chromosomes 10 and 11 described as t( 10; 11 )(p 13- 14;q 14-21 ). The breakpoint on chromosome 11 is telomeric to the /NT2 gene and the pHS11 probe at 11 q 13, and centromeric to the marker D 11536 localized to 11q 14.3-q22. 1 and the MLL gene at 11 q23. Similar translocations have been reported in various acute leukemias, principally of the monocytic lineage, and also in T-cell precursor acute lymphocytic leukemias. Further characterization of the genetic rearrangements in U937 may lead to the isolation of genes important in leukemogenesis and provide an in vitro system for their study. © 1995 Wiley-Liss, Inc.     

急性单核系白血病M4/M5中MLL基因重排的间期荧光原位杂交研究

目的　探讨间期荧光原位杂交 ( fluorescence in situ hybridization,FISH)技术对混合谱系白血病 ( mixed lineage leukemia,ML L)基因重排检测的价值 ;评估 ML L 重排在急性单核系白血病 M4 / M5中的发生率和预后意义。方法　采用骨髓直接法或短期培养法制备染色体 ,应用 R显带技术进行核型分析。采用地高辛标记的跨越 11q2 3断裂位点的单色 ML L探针和间期 FISH技术对 2 3例急性单核系白血病M4 / M5病例进行 ML L重排检测。结果　 R显带揭示 2 3例中 7例有涉及 11q2 3的易位 ,5例有其他核型异常 ,10例核型正常 ,1例核型分析失败。 FISH研究显示 12例有 ML L重排 ,包括 R显带检出 11q2 3异常的7例。结论 FISH技术检测 ML L重排的敏感性明显高于常规细胞遗传学技术 ;ML L重排与急性单核系白血病 M4 / M5高度相关 ,是预后不良的指标     

MLL translocations with concurrent 3' deletions: interpretation of FISH results

Rearrangements involving the MLL gene at 11q23 occur in a clinically relevant subgroup of patients with acute lymphoblastic leukemia (ALL) at all ages, and therefore their accurate identification at diagnosis is important. It has become commonplace to screen ALL patients for rearrangements of MLL using a dual-color fluorescence in situ hybridization (FISH) assay. We report on 12 ALL patients with an unusual FISH result consisting of the following signal pattern: one 5' green, no 3' red, and one/two fusion signals. This configuration is consistent with a MLL translocation and simultaneous deletion of 3' MLL-a well-established phenomenon-which has been interpreted as a positive result. G-banded and complementary metaphase FISH analyses confirmed an 11q23/MLL translocation in 8 of the 12 cases, whereas in one case, the identification of a del(11)(q23) was restricted to G-banded analysis only. In three cases, an MLL rearrangement was excluded by extensive FISH analysis and/or Southern blotting. In conclusion, the loss of the 3' MLL signal should not be assumed to be the result of a concurrent translocation and deletion event, and such aberrant FISH signal patterns should be investigated further by alternative methods for determining their MLL status.     

Cryptic ins(4;11)(q21;q23q23) detected by fluorescence in situ hybridization: a variant of t(4;11)(q21;q23) in an infant with a precursor B-cell acute lymphoblastic leukemia report of a second case

We report the chromosomal findings in a 4-year-old female with precursor B-cell acute lymphoblastic leukemia (ALL). The diagnostic karyotype showed an isochromosome 7q, i(7)(q10), as well as questionable rearrangements on 9p and 11q. Fluorescence in situ hybridization (FISH) studies on both interphase and metaphase cells using the MLL "break-apart" and the centromeric chromosome 4 probes were instrumental in the characterization of an MLL gene rearrangement, which was cryptic by conventional cytogenetic analysis. Specifically, the FISH pattern was consistent with an insertion of the 5' region of the MLL gene into chromosome 4 at band q21, most likely a variant t(4;11)(q21;q23). This is the second case of FISH detection of an ins(4;11) in ALL. Our case exemplifies the importance of FISH in the further characterization of precursor B-cell ALL cases without any apparent prognostically significant chromosomal abnormalities.     

Molecular and fluorescence in situ hybridization analysis of a 10;11 rearrangement in a case of infant acute monocytic leukemia

Fluorescence in situ hybridization (FISH) analysis in a case of infant acute monocytic leukemia M5 revealed a complex rearrangement between chromosomes 10 and 11, leading to the disruption of the MLL gene. Using two painting probes for chromosomes 10 and 11 and a specific probe for the MLL gene localized on 11q23, we observed a paracentric inversion of the 11q13-q23 fragment translocated to 10p12. Molecular analysis showed that AF10 localized on 10p12 was the fusion partner gene of MLL in this rearrangement (10;11). This report underlined the usefulness of FISH and molecular techniques in identifying complex rearrangements.     

Two cases of acute myeloid leukemia with t(11;17) associated with varying morphology and immunophenotype: rearrangement of the MLL gene and a region proximal to the RARalpha gene

This report describes 2 cases of acute myeloid leukemia (AML), which based on the WHO classification would be classified as AML with an 11q23 (MLL) abnormality, but with contrasting morphologic and immunophenotypic profiles. One case had monocytic features (morphologically and immunophenotypically) with a t(11;17)(q23;q21), a previously identified variant translocation in acute promyelocytic leukemia (APL). The second case had morphologic and immunophenotypic features of APL associated with a t(11;17)(q23;q25). In both cases, fluorescence-in-situ hybridization (FISH) analysis demonstrated that the 11q23 breakpoint involved the MLL gene, but RARalpha was not involved in the 17q breakpoints. These cases illustrate the importance of FISH analysis to confirm the presence of a particular recurring rearrangement.     

Role of multiplex FISH in identifying chromosome involvement in myelodysplastic syndromes and acute myeloid leukemias with complex karyotypes: a report on 28 cases

Chromosomal abnormalities are found by conventional cytogenetic (CC) analysis in about 50% of myelodysplastic syndromes (MDS) and 70% of acute myeloid leukemias (AML). When cytogenetic abnormalities are complex, multiplex fluorescence in situ hybridization (M-FISH) can help clarify complex chromosomal abnormalities and identify rearrangements with prognostic value or cryptic translocations, which could be preliminary steps in identifying new genes. We studied by M-FISH 28 cases of MDS and AML with complex chromosomal abnormalities, 10 of them were therapy-related. M-FISH allowed the characterization of unidentified chromosomal material in 26 cases (93%). One or several unbalanced rearrangements were observed in 27 cases (96%), generally interpreted as deletions or additional material by CC. Among those translocations, 4 involved 3 chromosomes. Eighteen cryptic translocations undetected by CC were found in 13 cases. By FISH analysis using locus specific probes, TP53 deletion, additional copies of MLL, and additional copies or deletions of RUNX1/AML1 were observed in 16, 4, and 3 cases, respectively. Thus, M-FISH is an important tool to characterize complex chromosomal abnormalities which identified unbalanced and cryptic translocations in 96% and 46% of the cases studied, respectively. Complementary FISH helped us identify involvement of TP53, MLL, and RUNX1/AML1 genes in 82% of cases, confirming their probable role in leukemogenesis.     

Amplified, lost, and fused genes in 11q23-25 amplicon in acute myeloid leukemia, an array-CGH study

Gene amplifications occur rarely in hematologic neoplasms. We characterized two cases of acute myeloid leukemia (AML) with marker chromosomes and 11q23-25 amplicons. Case 1 was a 14-year-old male with an additional ring of chromosome 11 material as the sole karyotypic abnormality, as determined by G-banding and multicolor fluorescence in situ hybridization. Standard comparative genomic hybridization (CGH) showed amplification in 11q23-qter. However, the MLL gene, in 11q23, was not amplified by FISH. Case 2 was a 38-year-old male with the G-banding karyotype 51,XY,+8,+19,+3mar and with 11q22-qter amplification by standard CGH. This patient also had the MLL-LARG fusion gene. We used microarray-based CGH (array-CGH) to characterize the amplicons. In case 1, the amplified region in 11q24.3-25 (5.5 Mb) was continuous, and MLL was not amplified, as expected. In case 2, the amplicon was divided into two distinct parts, in 11q23.3 (1.2 Mb) and in 11q23.3-25 (13.3 Mb). It contained a loss ( approximately 1 Mb) in 11q23.3, and the amplicon breakpoint was in the middle of MLL. Although the amplicon size varied, the patients had a common amplified region in 11q24-25 that comprised 14 genes. Expression microarray of case 1 revealed that three of these genes, FLI1, NFRKB, and SNX19, were also overexpressed. The results indicate that the 11q24-q25 region may harbor new candidate oncogenes. In addition, the complex amplicon of case 2 suggests some intriguing chromosomal mechanisms.     

Chromosomal insertion involving MLL in childhood acute myeloblastic leukemia (M4)

Recurrent chromosomal rearrangements involving the 11q23 region have been described in various hematologic malignancies. Among these rearrangements, translocations are the most common mechanism involving the mixed lineage leukemia gene (MLL). Few cases of insertion have been reported and, to our knowledge, none of them involved MLL and chromosome 1. We report a complex karyotype in a childhood acute myelomonocytic leukemia (AML M4) involving the 11q23 region with an insertion between chromosomes 1 and 11 in addition to a translocation between chromosomes 11 and 22. This translocation was clarified by fluorescence in situ hybridization (FISH) analysis: 46,XY,ins(1;11)(q22q23;q13q23),t(11;22)(q13;q11q12). This finding also underlines the complementary contribution of conventional cytogenetic and FISH analysis to detect karyotypic complex abnormalities.     

逆转录-多重巢式聚合酶链反应技术在急性单核系白血病M4/M5 MLL基因重排检测中的应用

目的 探讨逆转录-多重巢式聚合酶链反应（多重PCR）技术在初诊M4／M5患者MLL基因重排检测中的价值。方法 采用骨髓直接或短期培养法制备染色体，应用R显带技术进行核型分析。采用多重PCR技术，检测40例初诊M4／M5患者中5种急性髓系白血病常见的MLL融合基因以及MLL部分串联重复。结果 R显带揭示7有涉及11q23的易位，包括t（6；11）（q27；q23）、t（9；11）（p21；q23）、t（11；17）（q23；q21）、t（11；19）（q23；p13．1），14例有其他核型异常，19例为正常核型。多重PCR证实了7例核型分析显示11q23易位标本中的6例，例3核型分析揭示46，XX，t（6；11）（q27；q23），多重PCR检测MLL/AF6为阴性；19例显带分析为正常核型标本中检出2例MLL部分串联重复。结论 多重PCR是对初诊M4／M5患者进行各种MLL重排筛检的有效方法。     

多探针荧光原位杂交检测急性髓系白血病常见细胞遗传学异常

目的:评价多探针荧光原位杂交(FISH)在检测急性髓系白血病(AML)常见细胞遗传学异常中的价值,探讨细胞遗传学异常与临床诊断、治疗、预后的关系。方法:采用针对AML/MDS的FISH多探针诊断系统,即以针对AML1/ETO融合基因、PML-RARα融合基因、CBFβ/MYH11融合基因、MLL基因、P53基因、Del(5q)、Del(7q)、Del(20q)8种DNA探针对40例患者进行多探针FISH检测,同时联合染色体核型、临床资料进行研究。结果:40例AML中,共22例多探针FISH检出了细胞遗传学改变,包括:AML1/ETO、PML-RARα、MLL基因断裂重排、Del(5q)、Del(7q)、P53基因缺失、8号染色体三体7种细胞遗传学异常。而常规染色体核型分析仅检出11例遗传学异常。多探针FISH与染色体核型分析的总阳性率分别为57.50%及27.50%。AML1/ETO、PML/RARα阳性者首次诱导化疗效果较理想;而Del(7q)、MLL基因断裂重排阳性、伴复杂细胞遗传学改变者可能预示不良预后。结论:FISH多探针诊断系统检测AML患者常见遗传学异常更省时、准确、高效,有利于完善白血病的分层诊断及指导临床个体化治疗。     

Comprehensive cytogenetic analysis including multicolor spectral karyotyping and interphase fluorescence in situ hybridization in lymphoma diagnosis. a summary of 154 cases

Cytogenetic analysis including multicolor spectral karyotyping (SKY) and interphase fluorescence in situ hybridization (FISH) was performed on 154 consecutive cases with suspected lymphoma. The cytogenetic results were reviewed in correlation with the final pathologic diagnosis. A diagnosis of lymphoma was established in 94 cases, with 16 Hodgkin lymphomas and 78 non-Hodgkin lymphomas (NHL). Cytogenetic results were obtained in 63 NHLs (81%); 61 of those showed abnormal karyotypes (97%). The t(14;18) or IGH-BCL2 fusion was detected in 83% (20/24) of follicular lymphomas and in 57% (12/21) of diffuse large B-cell lymphomas (DLBCL). The application of interphase FISH and SKY has contributed to a high detection rate of t(14;18) in DLBCLs. This study showed that genes at 1q25, 3p21, 3q21, 5q31, 6p23, 7q22, 8q11 approximately q12, 9q34, 11q23, 12q13, and 19q13.1 may have been involved as the less common changes in follicular lymphoma and DLBCL. Comparison of the recurrent secondary aberrations in the groups of follicular lymphoma and DLBCL revealed a pattern of clonal evolution from the changes rea(1)(p36), del(6q), +7, +12 or dup or trp(12)(q13q22), +der(18)t(14;18), and +21 in follicular lymphoma to the changes rea(1)(p36), del(6q), +6, +7, +9, rea(11)(q23), +12, -13 or del(13(q12q14), +18, +21, and +X in DLBCL. The clonal evolution of the secondary aberrations is thought to contribute to the progression of the disease. About 90% (16/18) of other types of NHL had abnormal karyotypes showing specific translocations or gene rearrangements consistent with the pathologic diagnosis. A comprehensive cytogenetics approach including SKY and interphase FISH using probes for specific genes, such as IGH, BCL2, CCND1, and ALK, is a very useful ancillary diagnostic tool for lymphomas. The combined approach also led to the identification of t(2;19)(p23;q13.1) as a new variant of t(2;5)(p23;q35) in a case of Ki-1-positive anaplastic large cell lymphoma with a null cell phenotype.