Childhood acute lymphoblastic leukemia with chromosomal breakpoints at 11q23

Twenty-one (5.7%) of 368 cases of acute lymphoblastic leukemia (ALL), studied fully for karyotype and immunophenotype, had breakpoints in the q23 region of chromosome 11. This abnormality resulted from reciprocal translocation in 17 cases [with chromosomes 4 (n = 5), 10 (n = 2), and variable chromosomes (n = 10)], from deletions in three cases, and from a duplication in one case. The 17 children with 11q23 translocations had higher leukocyte counts (P less than .01) and were more likely to be black (P less than .01) and younger (P = .08) as compared with each of the following non-11q23 translocation groups: t(1;19), t(9;22), random translocations, and cases without translocations. Event-free survival at 3 years for the 11q23 translocation group did not differ significantly from that of the t(1;19), t(9;22), or random translocation groups. Leukemic cells from ten of the 21 patients with an 11q23 structural chromosomal abnormality had an immunophenotype indicative of B-lineage ALL (HLA-DR+, CD19+, CD2-, CD3-); this was confirmed by the presence of rearranged immunoglobulin heavy-chain genes in seven cases. In eight of these ten B-lineage cases, the blasts were negative for expression of the CD10 antigen, indicating a primitive stage of B-cell development. Four cases were classified as T-cell ALL, and seven others were characterized by blasts that failed to react with our panel of lineage-associated monoclonal antibodies (MoAbs). Myeloid antigens were expressed by leukemic cells in three of the cases that were tested. The initial clinical features associated with translocations involving the 11q23 chromosomal region may define a distinct subtype of ALL. Whether the constellation of findings relates to a breakpoint at 11q23 per se or to the specific translocation will require further study.     

Heterogeneity in the breakpoints of chromosome 19 among acute leukemia patients with the t(11;19)(q23;p13) translocation

Gene probes for insulin receptor (INSR) and c-ets-1 were hybridized to metaphase cells from three leukemic patients with the t(11;19)(q23;p13) translocation. Patients 1 and 2 were diagnosed as acute lymphocytic leukemia (ALL) (L2), and patient 3, as acute myelogenous leukemia (AML) (M4). The c-ets-1 gene was demonstrated to have translocated from chromosome 11 to the short arm of the rearranged chromosome 19 (19p+) in all three patients. On the other hand, the INSR gene translocated from chromosome 19 to the rearranged chromosome 11 (11q-) in the AML case, but remained on the rearranged chromosome 19 in the two ALL cases. Thus, the breakpoints of chromosome 19 are different among the patients studied, proximal to the INSR gene locus in the AML case and distal in the two ALL cases. Consequently, the c-ets-1 gene and the INSR gene remain separated in the AML case, whereas they become close to each other in the two ALL cases. Rearrangement of these two genes was studied in the two ALL patients, with no positive data being obtained. The results suggest that there may be heterogeneity in the breakpoints of chromosome 19 among the t(11;19)-associated acute leukemias.     

FISH detected 11q23 microdeletion and translocation at the long arm of chromosome 11 in a child with normal karyotypic acute lymphoblastic leukemia

We report on a 6-year-old girl with acute lymphoblastic leukemia (ALL) with 11q23 microdeletion and translocation at the long arm of chromosome 11, which were detected by fluorescence in situ hybridization (FISH) but not by conventional cytogenetics. She was hospitalized because of fever and generalized bone pain. Results of peripheral blood examination included a WBC of 5,400/microliter with 12% lymphoblasts. Bone marrow studies showed 75% of early pre-B lineage lymphoblasts with L1 morphology. G-banding chromosome analysis demonstrated a normal karyotype. However, FISH using mixed lineage leukemia (MLL) and 11q subtelomere probes demonstrated 11q23 microdeletion and translocation at the long arm of chromosome 11 to an undefined chromosome. MLL rearrangement was not detected by Southern blotting analysis. The patient achieved complete remission 15 days after receiving high-risk group chemotherapy of the Kyoto University Pediatric Hematology/Oncology Study Group and has remained in complete remission for more than 30 months. Since MLL/11q23 abnormalities confer a poor prognosis in childhood ALL, the accurate detection of such abnormalities is of paramount significance in assigning individual cases to risk categories. The findings from the present case and recent literature indicate that the FISH-based approach is complementary to conventional cytogenetics, and should be systematically used in childhood ALL at diagnosis.     

Chromosome 11q23 translocations in both infant and adult acute leukemias are detected by in situ hybridization with a yeast artificial chromosome.

The yeast artificial chromosome (YAC-13HH4), which spans a 440-kb region of DNA just distal to the CD3 locus on chromosome 11 at band q23, has been used to characterize a range of chromosomal translocations in acute leukemias from both adults and infants. In situ hybridization was performed on metaphase cells from bone marrow of 17 leukemias and two cell lines with a variety of chromosome 11q23 abnormalities. It was established that in infant leukemias the translocations t(11;19), t(4;11), and t(5;11) had occurred in the region defined by YAC 13HH4. Additionally, the translocations t(4;11), t(6;11), t(9;11), t(X;11), and t(10;11) in other leukemias were found to disrupt the same region of chromosome 11q23, although an exception was found in one t(6;11) translocation for which the breakpoint was distal to the YAC. One patient had a t(9;11) translocation in a therapy-related leukemia, suggesting that this class of etoposide-related malignancy has similar breakpoints to those occurring in de novo leukemias. An example of a lymphoma-derived translocation t(4;11) was shown to involve a deletion of the region defined by YAC 13HH4. A leukemia with a deletion on chromosome 11 (q23-q25) was also studied and it was shown that the YAC sequence was unaffected. It was concluded that, with a few exceptions, the translocations at 11q23 in a wide range of acute infant and adult leukemias occur in a common region and may result from a common underlying mechanism.     

Mapping of leukaemia-associated breakpoints in chromosome band 3q21 using a newly established PAC contig

Chromosome aberrations affecting band 3q21 are associated with a particularly poor prognosis in patients with acute myeloid leukaemia. To facilitate the molecular characterization of such rearrangements, we established a PAC contig covering the relevant genomic region. Using these PACs as probes in fluorescence in situ hybridization (FISH) experiments, we showed that a number of 3q21 breakpoints in patient samples map to a previously defined 'breakpoint cluster region'. Others, however, are located at varying distances centromeric of it. These results have important implications in the search for genes affected by 3q21 rearrangements.     

Mapping of four distinct BCR-related loci to chromosome region 22q11: order of BCR loci relative to chronic myelogenous leukemia and acute lymphoblastic leukemia breakpoints.

A probe derived from the 3' region of the BCR gene (breakpoint cluster region gene) detects four distinct loci in the human genome. One of the loci corresponds to the complete BCR gene, whereas the others contain a 3' segment of the gene. After HindIII cleavage of human DNA, these four loci are detected as 23-, 19-, 13-, and 9-kilobase-pair fragments, designated BCR4, BCR3, BCR2, and BCR1, respectively, with BCR1 deriving from the original complete BCR gene. All four BCR loci segregate 100% concordantly with human chromosome 22 in a rodent-human somatic cell hybrid panel and are located at chromosome region 22q11.2 by chromosomal in situ hybridization. The BCR2 and BCR4 loci are amplified in leukemia cell line K562 cells, indicating that they fall within the amplification unit that includes immunoglobulin lambda light chain locus (IGL) and ABL locus on the K562 Philadelphia chromosome (Ph1); additionally, in chronic myelogenous leukemia-derived mouse-human hybrids retaining a Ph1 chromosome in the absence of the 9q+ and normal chromosome 22, BCR2 and BCR4 loci are retained, whereas the 3' region of BCR1 and the BCR3 locus are lost, indicating that BCR3 is distal to BCR1 on chromosome 22. Similarly, in mouse-human hybrids retaining a Ph1 chromosome derived from an acute lymphoblastic leukemia-in the absence of the 9q+ and 22, only BCR2 and BCR4 loci are retained, indicating that the breakpoint in this acute lymphoblastic leukemia, as in chronic myelogenous leukemia, is proximal to the BCR1 3' region, but distal to the IGLC locus and the BCR2 and BCR4 3' loci. Thus, the order of loci on chromosome 22 is centromere----BCR2, BCR4, and IGL----BCR1----BCR3----SIS, possibly eliminating BCR2 and BCR4 loci as candidate targets for juxtaposition to the ABL gene in the acute lymphoblastic leukemia Ph1 chromosome.     

Isolation of a yeast artificial chromosome spanning the 8;21 translocation breakpoint t(8;21)(q22;q22.3) in acute myelogenous leukemia.

The 8;21 translocation is one of the most common specific rearrangements in acute myelogenous leukemia. We have identified markers (D21S65 and a Not I boundary clone, Not-42, referred to as probe B) flanking the chromosome 21 translocation breakpoint (21q22.3) that demonstrate physical linkage in normal genomic DNA, by using at least three restriction endonucleases (Not I, Sac II, and BssHII), and that are located not more than 250-280 kilobases apart. Pulsed-field gel analysis of DNA from somatic cell hybrids containing the 8;21 translocation chromosomes demonstrates rearrangement of these markers. A 470-kilobase yeast artificial chromosome, YAC-Not-42, has been isolated that contains both probes. Mapping of lambda subclones constructed from YAC-Not-42 suggests that greater than 95% (25/26 probes tested) of the yeast artificial chromosome DNA is located on the proximal (D21S65) side of the breakpoint. In situ hybridization studies using metaphase chromosomes from five acute myelogenous leukemia patients with the 8;21 translocation confirmed these results and demonstrated the translocation of probe B to the derivative chromosome 8. A chromosome walk of approximately 39 kilobases from probe B has allowed identification of the breakpoint in DNA from a somatic cell hybrid containing the derivative chromosome 8. Since probe B contains conserved DNA sequences and is in close proximity to the translocation breakpoint, it may represent a portion of the involved gene on chromosome 21.     

Clinical and hematologic characteristics in acute leukemia with 11q23 translocations

We studied the clinical, morphological, and immunologic characteristics of 11 patients with 11q translocation-associated acute leukemia. There were three patients with t(9;11)(p22;q23), one with a variant of the t(9;11), three with t(11;19)(q23;p13), two with t(1;11)(p32;q23), one with t(10;11)(p15;q22or23), and one with t(11;17) (q23;q25). The breakpoints in chromosome 11 clustered in band q23. The morphological feature was FAB-M5 in two patients, FAB-M2 in one, FAB-L1 in six, and lymphoblastic lymphoma in one. The remaining patient underwent morphological changes from FAB-L1 seen at the time of diagnosis to M5b at relapse. Immunologic marker studies in ten patients revealed that one had T cell type; another pre-B cell type; three CALLA- Ia- non-T, non-B type; two CAL-LA- Ia+ non-T, non-B type; two monocytic type (positive Fc-receptor); and the remaining one underwent phenotypic changes from CALLA+ Ia+ non-T, non-B type to monocytic type. The patients were usually young; five were under 1 year and two were 9 and 13 years. Hyperleukocytosis was observed in eight of the ten patients with acute leukemia, and two of the eight died of intracranial hemorrhage within two days of admission, associated with disseminated intravascular coagulation. These findings indicate that leukemia with the 11q23 translocation share certain characteristics in common, irrespective of the recipient chromosome, even though the latter may have some influence on the morphological and immunologic phenotype. Our data provide a hypothesis that multipotent stem cells are involved in the genesis of the 11q translocation-associated leukemia.     

ALL-1 gene at chromosome 11q23 is consistently altered in acute leukemia of early infancy

Early infancy (< 1 year of age), massive tumor cell burden, and extremely poor prognosis are characteristic features of a particular subset of childhood acute leukemias (AL). In these cases, chromosome aberrations at the 11q23 band are the most frequently reported cytogenetic abnormalities. We have recently cloned a genetic locus named ALL-1, in which DNA breakpoints are clustered in leukemic patients with 11q23 aberrations. Analysis of the ALL-1 genomic configuration in DNA from 15 infants with AL showed specific ALL-1 rearrangements in 12 cases (80%), including 5 with normal karyotypes. These findings indicate that a consistent genetic defect underlies this particular leukemic subset.     

Molecular cloning of the breakpoint of t(11;22)(q23;q11) chromosome translocation in an adult acute myelomonocytic leukaemia

Southern blot analysis with a cDNA probe of MLL indicated that the breakpoint is in a Bam HI 8.3 kb fragment which carries the exon 5–11 of MLL gene in DNA from an adult acute myelomonocytic leukaemia with a t(11;22)(q23;q11) translocation. The structural analysis of the rearranged MLL locus demonstrated that the breakpoint is localized between exon 8 and 9 of MLL locus. The normal counterpart fused to the MLL locus was proved to be derived from chromosome 22q11( AF-22 ) by somatic cell hybrids analysis and FISH. By FISH, AF-22 locus was localized to the region more centromeric to the BCR gene.     

Clinical features of adult acute leukemia with 11q23 abnormalities in Japan: a co-operative multicenter study

To clarify the clinical features of adult patients with acute leukemia (AL) with 11q23 abnormalities, we performed a retrospective analysis of data from 58 adult Japanese patients: 51 with acute myeloid leukemia (AML), and 7 with acute lymphoblastic leukemia (ALL). The incidences according to fusion partners in AML were: t(9;11), 31.3%; t(11;19), 27.4%; t(6;11), 21.5%. The incidence of patients with t(11;19) was higher than those in the US and Europe, and the incidence of t(4;11) was lower than that in childhood. The results indicated the poor prognosis of AML with 11q23 abnormalities regardless of the fusion partners. AML patients with 11q23 aged <60 years in the first CR who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) showed a more favorable outcome than those treated without allo-HSCT, although the differences were not statistically significant (P = 0.322 for DFS, P = 0.138 for OS). This result suggests that treatment strategies including allo-HSCT may be considered in the first CR in cases of AML with 11q23 abnormalities. However, further studies involving a large number of cases are required to assess the effect of allo-HSCT on adult AL with 11q23 abnormalities.     

Molecular cloning of the breakpoints of a complex Philadelphia chromosome translocation: identification of a repeated region on chromosome 17.

Complex translocations in chronic myelogenous leukemia involve various chromosomes, in addition to chromosomes 9 and 22, in a nonrandom fashion. We have analyzed the DNA from leukemia cells characterized by a complex translocation, t(9;22;10;17)(q34;q11;p13;q21), by using the techniques of Southern blot hybridization, in situ hybridization, and molecular cloning; one of the breakpoints is at 17q21, a band that is frequently involved in complex 9;22 translocations. All of the breakpoint junctions and the corresponding normal sequences from the four involved chromosomes have been molecularly cloned. Restriction mapping is consistent with a simple concerted exchange of chromosomal material among the four chromosomes, except that additional changes appeared to have occurred within the chromosome 17 sequences. The cloned sequences on chromosome 17 at band q21 were found to be repeated in normal cells. By fluorescence in situ hybridization, a strong signal is seen at 17q21, but a weaker signal is also present at 17q23. By comparison with other primate species, an inversion in chromosome 17 during evolution appears to be responsible for the splitting of the cluster of repeat units in normal human cells.     

11q23异常成人急性白血病临床及实验室特征分析

目的 研究11q23异常成人急性白血病(AL)的实验室资料与其临床特征和预后的关系.方法 对1992年8月至2003年11月中国协和医科大学血液学研究所收治的23例11q23异常的成人AL的临床和实验室资料进行回顾性分析.结果 23例11q23异常的患者中14例为急性髓性白血病(AML),7例为急性淋巴细胞白血病(ALL),1例为急性杂合细胞白血病(HAL),1例为急性未分化白血病(AUL).AML中以AML-M4及AML-M5为主,ALL中以前B-ALL为主.异常核型主要为11q23缺失(n=9)和t(4;11)(n=8).23例AL的中位存活时间为175 d,14例AML的中位存活时间为185 d,7例ALL的中位存活时间为167 d.结论 11q23异常AL在成人主要见于AML-M4及AML-M5和前B-ALL,具有高白细胞、易于髓外浸润、化疗缓解率低、预后差等临床特点,为预后不良的细胞遗传学改变.     

Hypo-triploid acute myeloid leukemia with isochromosome 11q.

A 78-year-old male developed acute myeloid leukemia (AML, M2) with an isochromosome 11q (i(11q)) in hypo-triploid populations. He died 2 months later from the leukemia without having responded to chemotherapy. We reviewed 12 cases in the literature with i(11q) in hematopoietic neoplasms and found that the i(11q) is associated with complex chromosome abnormalities and with elderly patients. Ten out of the 13 patients had an AML phenotype, and they had poor response to chemotherapy and a short survival. The i(11q) may be a non-random chromosome aberration in hematopoietic neoplasms.