A pediatric case of secondary leukemia associated with t(16;21)(q24;q22) exhibiting the chimeric AML1-MTG16 gene

Rare Hematologic Malignancies and Pre-Leukemic Entities in Children and Adolescents Young Adults

There are a variety of rare hematologic malignancies and germline predispositions syndromes that occur in children and adolescent young adults (AYAs). These entities are important to recognize, as an accurate diagnosis is essential for risk assessment, prognostication, and treatment. This descriptive review summarizes rare hematologic malignancies, myelodysplastic neoplasms, and germline predispositions syndromes that occur in children and AYAs. We discuss the unique biology, characteristic genomic aberrations, rare presentations, diagnostic challenges, novel treatments, and outcomes associated with these rare entities.

Prognostic impact of t(16;21)(p11;q22) and t(16;21)(q24;q22) in pediatric AML: a retrospective study by the I-BFM Study Group

To study the prognostic relevance of rare genetic aberrations in acute myeloid leukemia (AML), such as t(16;21), international collaboration is required. Two different types of t(16;21) translocations can be distinguished: t(16;21)(p11;q22), resulting in the FUS-ERG fusion gene; and t(16;21)(q24;q22), resulting in RUNX1-core binding factor (CBFA2T3). We collected data on clinical and biological characteristics of 54 pediatric AML cases with t(16;21) rearrangements from 14 international collaborative study groups participating in the international Berlin-Frankfurt-Münster (I-BFM) AML study group. The AML-BFM cohort diagnosed between 1997 and 2013 was used as a reference cohort. RUNX1-CBFA2T3 (n = 23) had significantly lower median white blood cell count (12.5 × 10⁹/L, P = .03) compared with the reference cohort. FUS-ERG rearranged AML (n = 31) had no predominant French-American-British (FAB) type, whereas 76% of RUNX1-CBFA2T3 had an M1/M2 FAB type (M1, M2), significantly different from the reference cohort (P = .004). Four-year event-free survival (EFS) of patients with FUS-ERG was 7% (standard error [SE] = 5%), significantly lower compared with the reference cohort (51%, SE = 1%, P < .001). Four-year EFS of RUNX1-CBFA2T3 was 77% (SE = 8%, P = .06), significantly higher compared with the reference cohort. Cumulative incidence of relapse was 74% (SE = 8%) in FUS-ERG, 0% (SE = 0%) in RUNX1-CBFA2T3, compared with 32% (SE = 1%) in the reference cohort (P < .001). Multivariate analysis identified both FUS-ERG and RUNX1-CBFA2T3 as independent risk factors with hazard ratios of 1.9 (P < .0001) and 0.3 (P = .025), respectively. These results describe 2 clinically relevant distinct subtypes of pediatric AML. Similarly to other core-binding factor AMLs, patients with RUNX1-CBFA2T3 rearranged AML may benefit from stratification in the standard risk treatment, whereas patients with FUS-ERG rearranged AML should be considered high-risk.

Acute myeloid leukemia with t(16;21)(q24;q22) and eosinophilia: case report and review of the literature

The t(16;21)(q24;q22), a rare chromosomal translocation involving chromosome 21 in de novo and therapy-related acute myeloid leukemia (AML), produces a RUNX1-CBFA2T3 fusion gene (previously AML1-MTG16) fusion gene. The translocation has been reported in 20 patients with AML, with eosinophilia present in 3 cases. Here we report a pediatric case of t(16;21)(q24;q22) in de novo AML with eosinophilia and suggest that eosinophilia is a hematologic characteristic of at least a subpopulation of AML with t(16;21)(q24;q22). A 4-year-old Korean girl was admitted with complaints of pale appearance and dizziness, and was diagnosed with acute myelomonocytic leukemia. On admission, laboratory evaluation revealed hemoglobin at 3.3 g/dL, platelets at 9.0 x 10(9)/L, and white blood cells at 9.1 x 10(9)/L with 10% eosinophils and 1% blasts. The bone marrow aspirate contained 31% blasts and 11% eosinophils. Flow cytometric analysis revealed the expression of CD13, CD14, CD19, CD33, CD34, and HLA-DR by the leukemic blasts. The karyotype was 47,XX, + 8,t(16;21)(q24;q22)[18]/46,XX[2]. Interphase fluorescence in situ hybridization analysis with a dual-color, dual-fusion translocation LSI AML1/ETO probe set for RUNX1 and RUNX1T1 produced three signals for each probe in 90% of interphases, but no fusion signals. We confirmed the presence of RUNX1-CBFA2T3 fusion transcripts with reverse transcriptase-polymerase chain reaction, using primers AML1ex5f1 and MTG16r2.

RUNX1-MTG16 fusion gene in acute myeloblastic leukemia with t(16;21)(q24;q22): case report and review of the literature

We report here a 73-year old female who was admitted for hematomas, dyspnea, and fever. Hematological data showed pancytopenia with 9% blast cells positive for CD13, CD33, CD34, HLAD2, and myeloperoxydase. A diagnosis of acute myeloid leukemia (AML) type 2 (FAB classification) was made. Banding cytogenetic techniques performed on bone marrow cells showed a 48,XX,+8,+9,del(9)(q22q33)x2 ,t(16;21)(q24;q22)[20]/46,XX[2] karyotype. Fluorescence in situ hybridization (FISH) with BACs covering the RUNX1 (alias AML1) (band 21q22) and MTG16 (band 16q24) gene showed a fusion of both genes. The t(16;21)(q24;q22) has been described in 16 AML cases, including ours. Eleven patients had received chemotherapy for a previous cancer, most of them were been treated with DNA-topoisomerase II inhibitors known to be associated with chromosomal translocations involving the RUNX1 gene. The significant homology between MGT16 and MTG8 suggests that the RUNX1-MTG16 fusion gene induced by the t(16;21)(q24;q22) is a variant of the RUNX1-MTG8 that shares similar activity.

Dexrazoxane-associated risk for acute myeloid leukemia/myelodysplastic syndrome and other secondary malignancies in pediatric Hodgkin's disease

PURPOSE

Pediatric Oncology Group (POG) studies 9426 and 9425 evaluated dexrazoxane (DRZ) as a cardiopulmonary protectant during treatment for Hodgkin's disease (HD). We evaluated incidence and risk factors of acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS) and second malignant neoplasms (SMNs).

PATIENTS AND METHODS

Treatment for low- and high-risk HD with doxorubicin, bleomycin, vincristine, and etoposide (ABVE) or dose-intensified ABVE with prednisone and cyclophosphamide (ABVE-PC), respectively, was followed by low-dose radiation. The number of chemotherapy cycles was determined by rapidity of the initial response. Patients were assigned randomly to receive DRZ (n = 239) or no DRZ (n = 239) concomitantly with chemotherapy to evaluate its potential to decrease adverse cardiopulmonary outcomes.

RESULTS

Ten patients developed SMN. Six of eight patients developed AML/MDS, and both solid tumors (osteosarcoma and papillary thyroid carcinoma) occurred in recipients of DRZ. Eight patients with SMN were first events. With median 58 months' follow-up, 4-year cumulative incidence rate (CIR) for AML/MDS was 2.55% +/- 1.0% with DRZ versus 0.85% +/- 0.6% in the non-DRZ group (P = .160). For any SMN, the CIR for DRZ was 3.43% +/- 1.2% versus CIR for non-DRZ of 0.85% +/- 0.6% (P = .060). Among patients receiving DRZ, the standardized incidence rate (SIR) for AML/MDS was 613.6 compared with 202.4 for those not receiving DRZ (P = .0990). The SIR for all SMN was 41.86 with DRZ versus 10.08 without DRZ (P = .0231).

CONCLUSION

DRZ is a topoisomerase II inhibitor with a mechanism distinct from etoposide and doxorubicin. Adding DRZ to ABVE and ABVE-PC may have increased the incidence of SMN and AML/MDS.

Treatment-related myelodysplastic syndrome/acute myeloid leukemia in survivors of childhood cancer--an update

Treatment-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/t-AML) is a devastating complication of treatment for childhood cancer. However, the major cause of premature death of children treated for cancer remains their primary cancer. The understanding of the presentation, incidence, predisposing risk factors and pathobiology of t-MDS/t-AML is increasing. This increased understanding has not yet been translated into improved outcomes of therapy for t-MDS/t-AML. However, newer approaches are under study.