Acute myeloid leukemia with t(16;21)(q24;q22) in a child

The t(16;21)(q24;q22), a rare chromosomal translocation observed mostly in therapy-related acute myelogenous leukemia (AML), produces a RUNX1-CBFA2T3 fusion gene. Here we report a de novo AML case of 1-year-old girl with t(16;21)(q24;q22). In this case, we demonstrated the RUNX1-CBFA2T3 fusion gene and established quantitative RT-PCR for detecting minimal residual disease.     

Childhood acute myeloid leukemia with bone marrow eosinophilia caused by t(16;21)(q24;q22)

Acute myeloid leukemia with abnormal bone marrow eosinophilia (AML-M4Eo) is often reported in core binding factor (CBF) leukemia, with translocations such as inv(16)(p13q22), t(16;16)(p13;q22) or t(8;21)(q22;q22); however, it is rarely reported with t(16;21)(q24;q22), which produces the RUNX1-CBFA2T3 (AML1-MTG16) chimera. The similarity between this chimera and RUNX1-RUNXT1 (AML1-MTG8) by t(8;21)(q22;q22) remains controversial. Adult leukemia with t(16;21)(q24;q22) was primarily therapy related, and shows poor prognosis; however, pediatric AML with this translocation was quite rare and tended to be de novo AML. We present here a 4-year-old boy with de novo AML-M4Eo and t(16;21)(q24;q22). He received chemotherapy and survived for more than 70 months without transplantation. We speculated that pediatric AML with t(16;21)(q24;q22) showed favorable prognosis, as with t(8;21)(q22;q22).     

Acute myelocytic leukemia with ins(21;8)(q22;q13q22) presenting with AML1/MTG8 chimeric mRNA

We report a case of acute myelocytic leukemia (AML) showing a chromosomal abnormality, ins(21;8), with AML1/MTG8 chimeric mRNA. The patient, a 73-year-old woman, was admitted to our hospital because of AML relapse. Bone marrow aspiration showed 44% blasts and ins(21;8)(q12;q13q22) by cytogenetic study. Moreover, the size of chimeric AML1/MTG8 mRNA detected by RT-PCR in this case was shorter than that of previously reported. The patient was diagnosed as having relapse of AML (M2), but achieved complete remission with DCP therapy. Four months later, extramedullary relapse occurred, and this was followed five months later by bone marrow relapse. However, the patient again achieved complete remission. Most cases of AML1/MTG8 fusion gene are caused by t(8;21), and only very rarely by ins(21;8). In this case, the AML1/MTG8 fusion gene is thought to have been involved in the onset of leukemia.     

Distinctive immunophenotypic features of t(8;21)(q22;q22) acute myeloblastic leukemia in children.

Thirty cases of newly diagnosed pediatric acute myeloblastic leukemia (AML) with French-American-British (FAB) M2 morphology were analyzed with cytogenetics and a comprehensive panel of monoclonal antibodies reactive with lymphoid-, natural killer (NK)-cell-, and myeloid-associated antigens. The t(8;21)(q22;q22), or t(8;21;V)(q22;q22;V), translocation was identified in 16 of the 30 cases. Cases with the t(8;21) did not differ significantly from the remaining M2 cases with respect to expression of CD11b, CD13, CD14, CD15, CD33, CD34, CD36, CD41a, CD42b, CDw65, TdT, or HLA-DR. Expression of the B-cell antigen CD19 was detected in 13 of the 16 t(8;21) cases (81%), but in only 1 of the 14 (7%) other M2 cases (P = .00006). Expression of the CD56 NK-cell antigen was also significantly more frequent among t(8;21) cases (63% v 14%; P = .01). Coexpression of CD19 and CD56 was found only in the t(8;21) group (9 of 16 cases, P = .0009). Furthermore, this phenotype was not found in 48 evaluable cases of de novo AML of the FAB M1, M3, M4, M5, or M7 subtypes. The 14 M2 AML cases lacking the t(8;21) commonly expressed CD2 (n = 5) or CD7 (n = 8). However, no case with the t(8;21) expressed either antigen (P = .01 and .0005, respectively). Thus, the t(8;21) biologic subgroup of pediatric M2 AML has distinct immunophenotypic characteristics that distinguish it from other types of de novo AML.     

Nonmyeloablative allogeneic bone marrow transplantation for orbital granulocytic sarcoma associated with t(8;21)(q22;q22) in acute myeloid leukemia

We report a nonmyeloablative allogeneic bone marrow transplant (allo-BMT) from an HLA-matched unrelated donor in a case of acute myeloid leukemia (AML), M2 with t(8;21)(q22;q22) and the presence of orbital granulocytic sarcoma (GS), who had residual tumor after conventional chemotherapy. The course of BMT was well tolerated, with no major procedure-related toxicity. The residual orbital GS regressed completely 4 months after BMT. She is currently 19 months post BMT, disease-free. To our knowledge, this is the first reported pediatric patient with AML, GS and t(8;21)(q22;q22) who received a nonmyeloablative allo-BMT.     

Involvement of the AML1 gene in the t(3;21) in therapy-related leukemia and in chronic myeloid leukemia in blast crisis

A nonrandom translocation between chromosomes 3 and 21, t(3;21)(q26.2;q22) has been detected in patients with a myelodysplastic syndrome or acute myeloid leukemia after treatment (t-MDS/t-AML) for a primary malignant disease and in chronic myelogenous leukemia in blast crisis (CML-BC). In these patients, the breakpoint on chromosome 21 is at band 21q22. This band is also involved in the t(8;21)(q22;q22) detected in 40% of the patients with acute myeloid leukemia subtype M2 (AML-M2) de novo who have an abnormal karyotype. In the t(8;21), the AML1 gene is the site of the breakpoint on chromosome 21. The AML1 gene is transcribed from telomere to centromere, and in the t(8;21) the 5' part of AML1 is fused to the ETO gene on chromosome 8 to produce the chimeric AML1/ETO on the der(8) chromosome. We found that AML1 is also rearranged in two t-AML patients and in one CML-BC patient with the t(3;21), but the breakpoints are approximately 40 to 60 kb downstream to those of AML-M2 patients. This region contains at least one additional exon of AML1, as determined by using an AML1 cDNA as a probe in Southern blot analysis. The t(3;21) breakpoints for the remaining patients could not be determined because, by fluorescence in situ hybridization analysis, the breaks are outside of the region covered by the available probes.     

Acute myeloid leukemia with a RUNX1-RUNX1T1 t(1;21;8)(q21;q22;q22) novel variant: a case report and review of the literature

Variants of t(8;21)(q22;q22) account for approximately 3% of all t(8;21) in acute myeloid leukemia (AML). We report a 63-year-old female patient with AML, who showed a 3-way novel variant of t(8;21), t(1;21;8)(q21;q22;q22). She presented with gastric discomfort and splenomegaly, and her complete blood count was: white blood cell count 7.96 × 10(9)/l, with 7% blasts; hemoglobin 8.3 g/dl, and platelets 66 × 10(9)/l. Her bone marrow showed increased blasts (32.5%) with a basophilic cytoplasm, salmon-pink granules and Auer rods. Cytogenetic analysis revealed a karyotype of 46,XX,t(1;21;8)(q21;q22;q22), and fluorescence in situ hybridization confirmed a RUNX1-RUNX1T1 fusion signal on the derivative chromosome 8. After induction chemotherapy, the patient achieved complete remission and has been stable for 6 months. To the best of our knowledge, this is the first report on the novel variant of t(8;21) involving the breakpoint 1q21 and the third case with a translocation among chromosomes 1, 21 and 8. Although the clinical relevance of variant t(8;21) is still unclear, a review of 24 such cases in the literature does not imply a poorer prognosis of variant t(8;21) than of the classic t(8;21).     

Hemophagocytosis by leukemic blasts in a case of acute megakaryoblastic leukemia with t(16;21)(p11;q22).

We report the case of a 2-year-3-month-old boy with acute megakaryoblastic leukemia showing hemophagocytosis by leukemic blasts. The chromosome analysis of his bone marrow revealed t(16;21)(p11;q22). In addition to the present case, we found 4 other acute myeloid leukemia (AML) cases associated with hemophagocytosis and t(16;21)(p11;q22) in the literature, of which 3 were megakaryoblastic. Although the syndrome of AML with FAB-M4/5 morphology, t(8;16)(p11;p13), and erythrophagocytosis is well known, leukemic blasts of FAB-M7 morphology showing t(16;21)(p11;q22) may be underscored for their phagocytic activity.     

Acute Myelomonocytic Leukemia with Dysplastic Bone Marrow Eosinophils Showing t(5;17)(q13;q11) and a Secondary Chromosomal Aberration, inv(16)(p13q22)

inv(16)(p13q22) is associated with de novo acute myelomonocytic leukemia with dysplastic bone marrow eosinophils (AMML Eo), which has a relatively favorable clinical course with a longer remission duration and better survival prospects. On the other hand, t(5; 17)(q13;q11), although relatively rare, has been reported to be a component of complex chromosomal abnormalities in myelodysplastic syndromes and secondary acute myeloid leukemia (AML). We treated a 29-year-old woman with the first reported case of de novo AMML Eo with inv(16)(p13q22) in addition to t(5; 17)(q13;q11). Although she attained complete remission (CR) immediately after induction therapy, the disease recurred 1 year after the completion of consolidation therapies. She underwent HLA-matched unrelated allogeneic bone marrow transplantation (UBMT), together with a myeloablative conditioning regimen, after achieving a second CR and has survived without a recurrence for more than 24 months since UBMT. In general, certain secondary chromosomal abnormalities are associated with the phenotype of the disease, which retains its essential biologic characteristics established by the primary abnormality. Accordingly, the primary nature of the leukemic cells in this case differs from the findings for core-binding factor AML with inv(16)(p13q22). We believe this report is the first of de novo AMML Eo with t(5; 17)(q13;q11) showing as a secondary chromosomal aberration with inv(16)(p13q22).     

Low curative potential of bone marrow transplantation for highly aggressive acute myelogenous leukemia with inversion inv (3)(q21q26) or homologous translocation t(3;3) (q21;q26)

Structural rearrangements of the long arm of chromosome 3 involving bands 3q21 and 3q26 and leading either to a paracentric inversion inv (3)(q21q26) or a translocation between both homologous chromosomes – t (3;3)(q21q26) – have been reported in patients with acute myelogenous leukemia (AML), myelodysplastic syndromes, myeloproliferative disorders, and chronic myelogenous leukemia in blast crisis. We describe three patients with de novo AML with these structural abnormalities who received multiple courses of conventional chemotherapy followed by unrelated donor (n=2) and autologous (n=1) bone marrow transplantation (BMT). All three patients had early relapse: patients 1 and 2 had relapse 69 days and 306 days after BMT, respectively, and patient 3 immediately after autologous BMT. Despite further chemotherapy, they died without achieving another remission. These findings, together with other recorded similar cases, show that AML with structural abnormalities of the long arm of chromosome 3 as described has an extremely poor prognosis even with the most potent anti-leukemic treatment modalities. Received: 30 June 1999 / Accepted: 14 December 1999     

t(3;21)(q26;q22): a recurring chromosomal abnormality in therapy- related myelodysplastic syndrome and acute myeloid leukemia

We have identified an identical reciprocal translocation between the long arms of chromosomes 3 and 21 with breakpoints at bands 3q26 and 21q22, [t(3;21)(q26;q22)], in the malignant cells from five adult patients with therapy-related myelodysplastic syndrome (t-MDS) or acute myeloid leukemia (t-AML). Primary diagnoses were Hodgkin's disease in two patients and ovarian carcinoma, breast cancer, and polycythemia vera in one patient each. Patients had been treated with chemotherapy including an alkylating agent for their primary disease 1 to 18 years before the development of t-MDS or t-AML. We have not observed the t(3;21) in over 1,500 patients with a myelodysplastic syndrome or acute myeloid leukemia arising de novo or in over 1,000 patients with lymphoid malignancies. We have previously reported that the t(3;21) occurs in Philadelphia chromosome-positive chronic myelogenous leukemia (CML). Thus, the t(3;21) appears to be limited to t-MDS/t-AML and CML, both of which represent malignant disorders of an early hematopoietic precursor cell. These results provide a new focus for the study of therapy-related leukemia at the molecular level.     

B-Lymphoid and myeloid lineages biphenotypic acute leukemia with t(8;21)(q22;q22)

By analyzing the characteristics of morphology, immune phenotype, chromosome karyotype and clinical manifestations of six cases of B-lymphoid and myeloid lineages biphenotypic acute leukemia (BAL) with t(8;21)(q22;q22), a new subgroup of BAL was reported. Bone marrow eosinophilia (more than 5%) and pseudo-Chediak abnormalities were not found. Auer rods were also not identified in four of six cases. Immunophenotype revealed B-lymphoid and myeloid lineages positive, together with frequent and high expression of CD34 and CD33, and weak expression of HLA-DR. In addition to t(8;21) chromosomal translocation, deletion of Y chromosome and complex chromosome abnormalities were also found. Chemotherapy for myeloid and lymphoid leukemia simultaneously produced good response in the patients. BAL with t(8; 21)(q22; q22) might be a new subgroup of BAL, and it was suggested that the leukemia clone with t(8;21)(q22;q22) might have originated from an early phase of hematopoiesis, and AML1/ETO fusion gene might be related to differentiation of B lymphocyte.     

Additional acquisition of t(1;21)(p32;q22) in a patient relapsing with acute myelogenous leukemia with NUP98-HOXA9

We report a 29-year-old Japanese male with acute myelogenous leukemia (AML)-M4 with a cryptic t(7;11)(p15;p15), in which a chimeric NUP98-HOXA9 fusion was detected by polymerase chain reaction analysis and a chromosomal analysis showed 46,XY. The patient received intensive chemotherapy and underwent autologous stem cell transplantation, and remission was confirmed by the disappearance of NUP98-HOXA9. However, 6 months after transplantation, the patient relapsed; NUP98-HOXA9 was detected again and karyotypic analysis revealed 46,XY, t(1;21)(p32;q22). Fluorescent in situ hybridization (FISH) analysis using an AML1-ETO translocation dual probe, showed that the 21q22 breakpoint involved AML1 locus. A retrospective FISH analysis showed that t(1;21) was absent at onset. This is the first reported case with AML who had a cryptic t(7;11)(p15;p15), and additionally acquired t(1;21)(p32;q22) at relapse.     

Genomic DNA breakpoints in AML1/RUNX1 and ETO cluster with topoisomerase II DNA cleavage and DNase I hypersensitive sites in t(8;21) leukemia

The translocation t(8;21)(q22;q22) is one of the most frequent chromosome translocations in acute myeloid leukemia (AML). AML1/RUNX1 at 21q22 is involved in t(8;21), t(3;21), and t(16;21) in de novo and therapy-related AML and myelodysplastic syndrome as well as in t(12;21) in childhood B cell acute lymphoblastic leukemia. Although DNA breakpoints in AML1 and ETO (at 8q22) cluster in a few introns, the mechanisms of DNA recombination resulting in t(8;21) are unknown. The correlation of specific chromatin structural elements, i.e., topoisomerase II (topo II) DNA cleavage sites, DNase I hypersensitive sites, and scaffold-associated regions, which have been implicated in chromosome recombination with genomic DNA breakpoints in AML1 and ETO in t(8;21) is unknown. The breakpoints in AML1 and ETO were clustered in the Kasumi 1 cell line and in 31 leukemia patients with t(8;21); all except one had de novo AML. Sequencing of the breakpoint junctions revealed no common DNA motif; however, deletions, duplications, microhomologies, and nontemplate DNA were found. Ten in vivo topo II DNA cleavage sites were mapped in AML1, including three in intron 5 and seven in intron 7a, and two were in intron 1b of ETO. All strong topo II sites colocalized with DNase I hypersensitive sites and thus represent open chromatin regions. These sites correlated with genomic DNA breakpoints in both AML1 and ETO, thus implicating them in the de novo 8;21 translocation.     

Therapy-related acute promyelocytic leukemia with a t(9;22)(q34;q11) and t(15;17)(q22;q11 to approximately 12) subclone

The translocation (15;17) is a typical marker of acute promyelocytic leukemia, whereas t(9;22) is predominantly associated with chronic myelogenous leukemia, and seldom with acute myelogenous leukemia. Furthermore, the association between t(15;17) and t(9;22) in the same cell is extremely rare. We present a case of therapy-related acute promyelocytic leukemia (t-APL) with a subclone accompanied by karyotype 46, XX, t(9; 22)(q34;q11), t(15 ;17)(q22;11 to approximately 12) at onset. A 75-year-old woman was diagnosed as having non-Hodgkin lymphoma of the thyroid gland in July 1997. She was treated with a CHOP-like regimen, but complete remission (CR) was not achieved. She then underwent surgical resection of her thyroid gland, and was treated with etoposide (total dose 16775 mg) from February 1998 to May 2000. In June 2000, having developed t-APL, she was referred to our department. The patient attained CR following treatment with chemotherapy containing all-trans retinoic acid. Ten months later she relapsed, but lost the t(9;22), while maintaining the t(15;17).