Clinical and cytogenetics studies on acute myeloid leukemia with abnormality of chromosome 11

OBJECTIVE: To investigate the incidence of chromosome 11 abnormality in acute myeloid leukemia and its relationship with the clinical aspects and prognosis. METHODS:Conventional cytogenetic analysis of R-band was used to detect the abnormalities of chromosome 11 in 356 acute myeloid leukemia patients. RESULTS: Thirty-four out of 356 patients (9.55%) had abnormalities of chromosome 11, of which 20 (58.8%) involved in 11q23, 7 (19.9%) had translocations involving 11p15, 5 (14.7%) had-11, and the rest had other abnormalities such as +11, and t(11;14). The incidence of 11q23 involvement in M4 and M5 was higher than other subtypes of acute myeloid leukemia (AML). Ten cases with 11q23 abnormality had additional cytogenetic aberrations. In 30 cases treated with chemotherapy, 13 cases acquired complete remission (CR). The CR rate was lower than that of whole cases of acute myeloid leukemia(34.3% versus 64.0%). The CR rate of AML with 11q23 abnormality was lower than that of AML with normal karyotype (25% versus 55.6%). In other 10 patients with additional chromosome aberrations, the CR rate was lower than that of AML with 11q23 alone. In 7 patients with translocations at 11p15, only 3 patients acquired CR, and 2 patients relapsed early. Only 2 patients acquired CR in 5 patients with-11. CONCLUSION: 11q23 was a frequent aberration in chromosome 11 anomaly, which was often detected in M4 and M5. It might be associated with the pathogenesis of acute monolytic leukemia. The patients with chromosome 11 anomaly had poorer prognosis.     

Molecular cytogenetic analysis of gene rearrangements in childhood acute lymphoblastic leukemia

The aims of this study were to estimate the incidences of BCR/ABL, MLL, TEL/AML1 rearrangements, and p16 deletions in childhood acute lymphoblastic leukemia (ALL), to identify new abnormalities, and to demonstrate the usefulness of interphase fluorescence in situ hybridization (FISH). We performed G-banding analysis and FISH using probes for BCR/ABL, MLL, TEL/AML1 rearrangements, and p16 deletions on 65 childhood ALL patients diagnosed and uniformly treated at a single hospital. Gene rearrangements were identified in 73.8% of the patients using the combination of G-banding and FISH, while the chromosomal abnormalities were identified in 49.2% using G-banding alone. Gene rearrangements were disclosed by FISH in 24 (72.7%) of 33 patients with normal karyotype or no mitotic cell in G-banding. Among the gene rearrangements detected by FISH, the most common gene rearrangement was p16 deletion (20.3%) and the incidences of others were 14.1% for TEL/AML1, 11.3% for MLL, and 1.8% for BCR/ABL translocations. Infrequent or new aberrations such as AML1 amplification, MLL deletion, ABL deletion, and TEL/AML1 fusion with AML1 deletion were also observed. We established the rough incidences of gene rearrangements in childhood ALL, found new abnormalities and demonstrated the diagnostic capability of interphase FISH to identify cryptic chromosome aberrations.     

Lymphoblastic leukemia with lymphomatous features associated with abnormalities of the short arm of chromosome 9

Patients with acute lymphoblastic leukemia (ALL) who present with bulky disease of the lymph nodes, spleen, or mediastinum--so-called "lymphomatous ALL"--appear to represent a distinct subgroup among patients with ALL of T-cell lineage who have different clinical findings, but the biologic basis for these differences is not known. While studying 65 patients with lymphoblastic leukemia whose karyotype was determined at diagnosis, we compared the findings in 8 patients with lymphomatous ALL and 57 patients whose presentations were more typical of ALL. Six patients with lymphomatous ALL had karyotypic abnormalities leading to loss of bands p21-p22 on the short arm of chromosome 9. The mechanisms varied and included deletions, unbalanced translocations, or loss of the entire chromosome. Only 1 of the 57 patients without lymphomatous ALL had an abnormality of chromosome 9 at diagnosis (P less than 0.001). These findings indicate that loss of chromosomal material in the region of 9p21-p22 is closely associated with lymphomatous ALL; by analogy with retinoblastoma, in which gene deletions are associated with an enzyme deficiency, this disease may be related to the loss of the enzyme methylthioadenosine phosphorylase, previously reported in some of these patients.     

New recurrent balanced translocations in acute myeloid leukemia and myelodysplastic syndromes: Cancer and leukemia group B 8461

Acquired chromosome abnormalities in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are among the most valuable determinants of diagnosis and prognosis. In search of new recurrent balanced translocations, we reviewed the Cancer and Leukemia Group B (CALGB) cytogenetics database containing pretreatment and relapse karyotypes of 4,701 adults with AML and 565 with MDS who were treated on CALGB trials. We identified all cases with balanced structural rearrangements occurring as a sole abnormality or in addition to one other abnormality, excluded abnormalities known to be recurrent, and then reviewed the literature to determine whether any of what we considered unique, previously unknown abnormalities had been reported. As a result, we identified seven new recurrent balanced translocations in AML or MDS: t(7;11)(q22;p15.5), t(10;11)(q23;p15), t(2;12)(p13;p13), t(12;17)(p13;q12), t(2;3)(p21;p21), t(5;21)(q31;q22), and t(8;14)(q24.1;q32.2), and additionally, t(10;12)(p11;q15), a new translocation in AML previously reported in a case of acute lymphoblastic leukemia. Herein, we report hematologic and clinical characteristics and treatment outcomes of patients with these newly recognized recurrent translocations. We also report 52 unique balanced translocations, together with the clinical data of patients harboring them, which to our knowledge have not been previously published. We hope that once the awareness of their existence is increased, some of these translocations may become recognized as novel recurring abnormalities. Identification of additional cases with both the new recurrent and the unique balanced translocations will enable determination of their prognostic significance and help to provide insights into the mechanisms of disease pathogenesis in patients with these rare abnormalities. © 2012 Wiley Periodicals, Inc.     

Association of MTHFR polymorphisms and chromosomal abnormalities in leukemia

Genetic variation in MTHFR gene might explain the interindividual differences in the reduction of DNA repaired and the increase of chromosome breakage and damage. Nowadays, chromosomal rearrangement is recognized as a major cause of lymphoid malignancies. In addition, the association of MTHFR polymorphisms with aneuploidy was found in several studies, making the MTHFR gene as a good candidate for leukemia etiology. Therefore, in this study, we investigated the common sequence variation, 677C>T and 1298A>C in the MTHFR gene of 350 fixed cell specimens archived after chromosome analysis. The distribution of the MTHFR polymorphisms frequency was compared in leukemic patients with structural chromosome abnormality and chromosome aneuploidy, as well as in those with no evidence of chromosome abnormalities. We observed a significant decrease in the distribution of T allele in 677C>T polymorphisms among patients with chromosomal abnormalities including both structural aberration and aneuploidy. The same significance result also found in patients with structural aberration when compare with the normal karyotype patients. Suggesting that polymorphism in the MTHFR gene was involved in chromosome abnormalities of leukemia. However, further investigation on the correlation with the specific types of chromosomal aberrations is needed.     

43例急性白血病的染色体观察

报告43例初治急性白血病的染色体检查。结果核型异常总检出率为44．2％，急性淋巴细胞白血病（ALL）和急性非淋巴细胞性白血病（ANLL）的核型异常检出率分别为58．3％、38．7％。核型异常表现主要为数目异常，数目异常15例，结构异常3例，结构、数目均异常1例。1例M_2Ph染色体阳性。分析核型与疗效的关系，发现ALL诊断时染色体众数＞50、超二倍体的病人预后并不好。     

11q23 abnormalities in patients with acute myelogenous leukemia and myelodysplastic syndrome as detected by molecular and cytogenetic analyses

11q23 chromosomal abnormalities and rearrangement of the mixed lineage leukemia (MLL) gene are important prognostic factors in acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). However, the presence of 11q23 abnormalities does not always correlate with that of MLL gene rearrangement. We retrospectively compared the occurrence of 11q23 abnormalities (measured by karyotyping) and MLL gene rearrangement (measured by Southern blotting) in bone marrow from 311 consecutive adult patients with AML or MDS. 11q23 abnormalities were found in 18 patients (5.8%), of whom 7 (39%) did not have the MLL gene rearrangement. MLL gene rearrangement was detected in 35 patients (11.2%). Of these 35 patients, only 11 (31%) had cytogenetic evidence of 11q23 abnormalities. None of the 21 patients with chronic myelomonocytic leukemia had 11q23 abnormalities or MLL gene rearrangement. 11q23 abnormalities were associated with shorter survival than was a diploid karyotype. Both cytogenetic and molecular studies should be performed to detect 11q23 abnormalities in patients with AML or MDS.     

Acute leukemia cytogenetics: an evaluation of combining G-band karyotyping with multi-color spectral karyotyping

We have, during a 12-month period, evaluated the adjuvant effect of combining G-band karyotyping and multi-color spectral karyotyping (SKY) in acute leukemia patients. Forty-four cases were evaluated; fewer cases than those routinely analyzed by G-band cytogenetics had mitoses left for SKY analysis. Of the 44 patients, 35 were acute myeloid leukemia (AML) and 9 acute lymphatic leukemia (ALL) cases. Twenty-seven of 35 AML and 7 of 9 ALL patients had an abnormal G-band karyotype. Thirteen of these 34 abnormal cases had a simple clonal chromosome aberration, and the remaining 21 cases had a complex karyotype. The SKY confirmed the simple karyotype in 11 and in 7 with a complex karyotype. In 13 of the cases with a complex karyotype, ambiguous structural aberrations were classified, in 6 of these, SKY disclosed cryptic translocations. Thus, SKY either extended or confirmed G-band karyotypes in 31 of 34 analyzed abnormal cases. Cases where SKY did not reveal the abnormal clone showed only few abnormal mitoses by G-banding (2/23, 2/25, and 4/27). Additional or confirmatory information was therefore obtained in 91% of analyzed cases, and SKY proved to be a valuable additional tool for hematologic cytogenetics.     

Complex karyotype abnormalities in pediatric acute myeloid leukemia

A majority of the data on the prognostic significance of distinct chromosome changes and combinations of them in pediatric acute myeloid leukemia (AML) has been derived from adult studies, with not numerous published data in pediatric patients. One of points needed to be clarified is prognostic significance of complex karyotype (at least 3 unrelated abnormalities). We investigated characteristic features of complex karyotype in newly diagnosed pediatric AML de novo. Cell clones with complex karyotype were found in 35 of 254 (13.8%) patients at the age from 0 to 15 years studied prior to therapy. The group was divided into 2 subgroups depending on presence of favorable chromosome abnormalities, i.e. (see symbols)(8;21), t(15;17) and inv(16). The abnormalities were absent in 20 cases (1st subgroup), in 15 remaining patients they were identified (2nd subgroup). In 2nd subgroup karyotypes were not so considerably changed and no adverse risk markers were detected as distinct from 1st subgroup. New data were obtained for complex karyotype differences of adult and pediatric AML. In the great majority (76%) of complex karyotypes in our adult patients chromosome abnormalities associated with adverse risk were found but in pediatric patients their frequency was significantly less (30%). The highest rate of complex karyotype we observed in children at the age from 0 to 3 years. Similar data were not published earlier. Complex karyotype is considered to be characteristic of older AML patients and in the majority of the patients the karyotype contains markers of adverse risk. Possibly, worse outcome in older AML patients is connected with the markers but not with multiple chromosome changes. New data of frequency and the peculiarities of complex karyotype in pediatric AML are important for understanding of AML pathogenesis and for development a more effective AML treatment.     

Six-year follow-up of the clinical significance of karyotype in acute lymphoblastic leukemia

To evaluate the importance of pretreatment karyotype in predicting long-term outcome in acute lymphoblastic leukemia (ALL), we performed a follow-up study of the 329 patients from the Third International Workshop on Chromosomes in Leukemia. Living patients have now been followed a minimum of 6 years. Patients were divided into ten groups according to pretreatment karyotype: no abnormalities, one of the following structural abnormalities [the Philadelphia chromosome, rearrangements involving 8q24, t(4;11), 14q+, 6q−] or, in the remaining cases, modal number (<46, 46, 47–50, >50). As previously reported for achievement and duration of complete remission, and overall survival, disease-free survival differed significantly (p < 0.001) among chromosome groups for both adults and children. Among children, karyotype was an independent prognostic factor for predicting disease-free survival. Because of the long follow-up, we now have been able to utilize statistical models to estimate the percentage of patients cured, according to karyotype alone and combined with other risk factors. Adults with the highest likelihood of cure (21–33%) were those patients with FAB-L1, a leukocyte count of 50,000/μl or less, and one of the following chromosome groups: greater than 50, 47–50, 6q−, or normal. In children these same characteristics were associated with the highest percentage of cure (58–71% cured). In addition, we identified several groups of children with less than 15% chance of cure who clearly need to be treated as high-risk patients at diagnosis. Future studies of patients who have received risk-adapted therapy based on these chromosome data are needed to determine if more intensive treatment will improve the outlook of patients with cytogenetically unfavorable types of ALL.     

Contribution of multiparameter genetic analysis to the detection of genetic alterations in hematologic neoplasia. An evaluation of combining G-band analysis, spectral karyotyping, and multiplex reverse-transcription polymerase chain reaction (multiplex RT-PCR)

We investigated 150 acute myeloid leukemia (AML) patients and 48 acute lymphoblastic leukemia (ALL) patients by multiplex RT-PCR to 7evaluate the adjuvant diagnostic effect, vis-à-vis G-banding and spectral karyotyping (SKY), and the potentials of this method for providing means for monitoring residual disease by real-time quantitative RT-PCR. An abnormal G-banded karyotype was found in 57% of AML and 68% of ALL cases. Ninety-six patients were investigated by SKY in parallel which extended or confirmed the G-banding finding in 94/96 cases. In patients with an abnormal G-banded karyotype, classification of chromosomes involved in structural aberrations by SKY was possible in 98% of the cases and SKY extended the G-banded karyotype in 34% of cases. In 32 cases, an mRNA hybrid was detected by PCR. These cases constitute 16% of the cases investigated at diagnosis (AML: 11% and ALL: 31%). In 13 of these cases, we detected an mRNA hybrid the equivalent of which was not found by G-banding or SKY (AML: 4% and ALL: 13%). By including multiplex RT-PCR, we were able to detect abnormalities in 62% of the investigated patients as opposed to 59% by G-banding. Genetic techniques complement each other and selection of relevant and targeted primer kits for the multiplex RT-PCR assay is recommended.     

Prognostic and biological importance of chromosome findings in acute lymphoblastic leukemia

At least 25 structural chromosomal abnormalities are now found in acute lymphoblastic leukemia (ALL). Many of the abnormalities are associated with particular clinical or blast cell features. Chromosomal translocation breakpoints in ALL are among those that define regions of the genome of oncogenic potential, the recognition of which has led to an improved understanding of the mechanisms of leukemogenesis. The prognostic importance of chromosome findings in ALL concerns demonstration of long-term survival in patients with high hyperdiploid leukemic clones and identification of patients with certain translocations who are at high risk of treatment failure and for whom alternative therapy such as bone marrow transplantation may be desirable. This review summarizes the more recent chromosomal findings in childhood and adult ALL and discusses how increasing recognition of structural change and adoption of alternative therapy for high-risk chromosomal groups may change the prognostic role of cytogenetics in this type of leukemia.     

Low incidence of TEL/AML1 fusion and TEL deletion in Korean childhood acute leukemia by extra-signal fluorescence in situ hybridization

TEL/AML1 fusion in acute leukemia results from cryptic translocation of chromosome 12 and 21, the presence of which suggests a favorable prognosis. The incidence of TEL/AML1 fusion in B-lineage ALL is approximately 25%, but the incidence in Korea has not yet been reported. To investigate the incidence of TEL/AML1 fusion and TEL deletion, bone marrow specimens from 77 Korean children with newly diagnosed acute leukemia were analyzed by FISH. We applied extra-signal FISH to discriminate a true TEL/AML1 fusion from a false-positive fusion signal. To determine the cut-off value of the TEL/AML1 fusion signal, 20 normal bone marrow specimens and 28 normal peripheral blood specimens were also analyzed. The frequency of patients with TEL/AML1 fusion was 13.3% (4 cases) among 30 B-lineage ALL and 9.5% among 42 ALL. One TEL/AML1 fusion-positive patient was also found among 4 acute biphenotypic leukemias. TEL/AML1 fusion was not found in any samples from patients with T-lineage ALL or AML. The incidence of TEL deletion was 6.7% (2 cases) among 30 B-lineage ALL and 4.8% among 42 ALL. The incidences of TEL/AML1 fusion and TEL deletion in Korean children with acute leukemia appear to be lower than those in other countries, suggesting a racial difference.     

Translocations involving 12p in acute myeloid leukemia: Association with prior myelodysplasia and exposure to mutagenic agents

Six cases of acute myeloid leukemia (AML) with translocations involving 12p are described. The patients were one child age 7 yrs and five adults with an age range of 20–66 yrs (median 46 yrs). In two patients AML followed treatment for acute lymphoblastic leukemia (ALL), in one case after 11 years disease-free survival. Of the remaining four patients, two had been occupationally exposed to possible mutagens and three had a previous myelodysplastic phase. Two patients achieved complete remission; survival for the six cases was between 1 and 24 months (median 6.5 months). The breakpoints in 12p occurred in p11, p12, and p13, indicating that several sites are important in these rearrangements, and it is suggested that t(12; 17)(p 11;q11) is a new nonrandom abnormality in AML.     

The presence of TEL/AML1 rearrangement and cryptic deletion of the TEL gene in adult acute lymphoblastic leukemia (ALL)

TEL/AML1 (also known as ETV6/RUNX1) rearrangement is the most frequent genetic change in childhood B-acute lymphoblastic leukemia (ALL) and is associated with a favorable prognosis. Its presence in adult ALL, however, has been questionable, and any association between TEL/AML1 rearrangement and clinical prognosis is unknown. To reveal the presence and incidence of the TEL/AML1 rearrangement in adult ALL, we applied fluorescence in situ hybridization (FISH). We conducted extra-signal, dual-color fluorescence in situ hybridization (ES-FISH) for TEL/AML1 rearrangement on bone marrow cells from 74 adult ALL patients and analyzed the survival time. We demonstrated the TEL/AML1 rearrangement in 2 patients (2.7%) among 74 patients with ALL. Of 74 adult ALL patients, 3 (4.0%) showed deletion of the TEL gene without TEL/AML1 rearrangement. The mean survival time of patients with TEL/AML1+ALL and patients with cryptic TEL deletion was 33 and 5 months, respectively, whereas the mean survival time of 53 TEL/AML1-ALL patients was 16.7 months. TEL/AML1 rearrangement is not unique in childhood ALL, and cryptic TEL deletion without TEL/AML1 rearrangement was more frequent than the TEL/AML1 rearrangement in adult ALL. We recommend TEL/AML1 FISH in adult ALL patients because conventional cytogenetic studies so far have yielded uninformative results.     

Secondary acute myeloid leukemia in children treated for acute lymphoid leukemia

We studied the risk of the development of acute myeloid leukemia (AML) during initial remission in 733 consecutive children with acute lymphoid leukemia (ALL) who were treated with intensive chemotherapy. This complication was identified according to standard morphologic and cytochemical criteria in 13 patients 1.2 to 6 years (median, 3.0) after the diagnosis of ALL. At three years of follow-up, the cumulative risk of secondary AML during the first bone marrow remission was 1.6 percent (95 percent confidence limits, 0.7 and 3.5 percent); at six years, it was 4.7 percent (2 and 10 percent). The development of secondary AML was much more likely among patients with a T-cell than a non-T-cell immunophenotype (cumulative risk, 19.1 percent [6 and 47 percent] at six years). Sequential cytogenetic studies in 10 patients revealed entirely different karyotypes in 9, suggesting the induction of a second neoplasm. In eight of these patients, the blast cells had abnormalities of the 11q23 chromosomal region, which has been associated with malignant transformation of a pluripotential stem cell. There was no evidence of loss of DNA from chromosome 5 or 7, a karyotypic change commonly observed in cases of AML secondary to treatment with alkylating agents, irradiation, or both. We conclude that there is a substantial risk of AML in patients who receive intensive treatment for ALL, especially in those with a T-cell immunophenotype, and that 11q23 chromosomal abnormalities may be important in the pathogenesis of this complication.     

伴7号染色体异常的急性白血病32例分析

目的探讨7号染色体异常在急性白血病中的发生率及预后意义。方法采用R带常规显带技术进行染色体检查,对410例急性白血病患者的核型进行分析。结果410例急性白血病患者中检出7号染色体异常患者32例,占7.8%;其中-7/7q-19例(59.4%),t(7;11)3例(9.4%),其他为少见的7号染色体改变der(7), 7,t(2;7),t(5;7),t(7;9),t(7;8),dic(1;7)。-7/7q-中,急性髓细胞白血病12例,其中M0、M1、M2型的-7/7q-发生率高于其他类型急性髓细胞白血病。32例患者中20例同时有其他染色体异常,最常见的是t(9;22)伴-7, 8,-5。30例进行正规化疗的患者,11例缓解,缓解率低于同期急性白血病的总缓解率(36.7%vs65.8%);伴-7/7q-的急性髓细胞白血病的缓解率低于染色体正常的急性髓细胞白血病患者(25%vs55.6%);伴-7/7q-的急性淋巴细胞白血病的缓解率与染色体正常的急性淋巴细胞白血病患者无差异(57.1%vs77.8%),但缓解的4例急性淋巴细胞白血病患者均于短期内复发。伴其他7号染色体异常的11例患者仅4例缓解。结论-7/7q-是7号染色体异常中最为常见的核型改变,且多见于急性髓细胞白血病的M0、M1、M2型,并可能与急性白血病的发病有关;伴7号染色体异常的急性白血病患者预后较差。     

Different characteristics identified by single nucleotide polymorphism array analysis in leukemia suggest the need for different application strategies depending on disease category

The purpose of this study was to evaluate the detection rate of chromosomal rearrangements in leukemia using single nucleotide polymorphism array (SNP‐A) in combination with metaphase cytogenetics (MC), with the aim of proposing a practical approach for clinical karyotyping applications of SNP‐A. The Genome‐Wide Human SNP Array 6.0 (Affymetrix, Santa Clara, CA) was applied in 469 patients with a variety of hematologic malignancies. Combined use of SNP‐A with MC improved the detection rate in comparison with MC alone: acute myeloid leukemia (AML) with normal karyotype (NK), 32% versus 0%; core binding factor (CBF)‐AML 40% versus 29%; myelodysplastic syndrome (MDS), 54% versus 39%; chronic myeloid leukemia (CML), 24% versus 3%; and acute lymphoblastic leukemia (ALL), 88% versus 63%. Different patterns of abnormalities (especially the type, size, and location) were noted in the leukemia subtypes. Copy neutral loss of heterozygosity lesions was detected in 23% of AML‐NK, 3% of CBF‐AML, 25% of MDS, 2% of CML, and 20% of ALL. SNP‐A also provided information on cryptic deletions and a variety of aneuploidies in ALL, while the benefit was minimal in CML. In conclusion, different patterns of abnormal lesions were presented according to the disease category, thus requiring a different approach of adopting SNP‐A‐based karyotyping among different leukemia subtypes. © 2012 Wiley Periodicals, Inc.