Childhood acute myeloid leukemia with CBFbeta-MYH11 rearrangement: study of incidence, morphology, cytogenetics, and clinical outcomes of Chinese in Hong Kong

High expression of microRNA-500 is associated with poor prognosis in patients with acute myeloid leukemia receiving allogeneic hematopoietic stem cell transplantation

MicroRNA-500 (miR-500) is a potential prognostic biomarker in a number of different types of cancer, such as prostate cancer and hepatocellular carcinoma. This study aimed to explore the clinical implications of miR-500 expression status in patients with acute myeloid leukemia (AML) that had received allogeneic hematopoietic stem cell transplantation (allo-HSCT). miR-500 expression status and clinical data were obtained from 74 patients with AML in the The Cancer Genome Atlas database receiving allo-HSCT. Patients with low expression level of miR-500 (miR-500_low) were significantly more likely to present with a French-American-British classification M2 subtype (P=0.003), and less likely to have the M5 subtype (P=0.040) compared with patients with high expression levels (miR-500_high). miR-500_low patients were associated with low-risk AML (P=0.003) and core-binding factor subunit b-myosin heavy chain 11 translocation mutation (P=0.021). There was a significant difference in nucleophosmin 1 (P=0.009), NRAS proto-oncogene GTPase/KRAS proto-oncogene GTPase (P=0.047) and PHD finger protein 6 (P=0.040) expression levels between the two groups. miR-500_high patients had a decreased overall survival (OS) time compared with the low expression group (P=0.035). Multivariate analysis revealed that miR-500 expression significantly affected OS time independent of other classical prognostic factors, such as age and common mutations. The analysis of survival curves further substantiated this result. The results obtained in the current study suggested that miR-500 may be a suitable prognostic marker for patients with AML receiving allo-HSCT.

Global characteristics of childhood acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) comprises approximately 5-10% of childhood acute myeloid leukemia (AML) cases in the US. While variation in this percentage among other populations was noted previously, global patterns of childhood APL have not been thoroughly characterized. In this comprehensive review of childhood APL, we examined its geographic pattern and the potential contribution of environmental factors to observed variation. In 142 studies (spanning >60 countries) identified, variation was apparent-de novo APL represented from 2% (Switzerland) to >50% (Nicaragua) of childhood AML in different geographic regions. Because a limited number of previous studies addressed specific environmental exposures that potentially underlie childhood APL development, we gathered 28 childhood cases of therapy-related APL, which exemplified associations between prior exposures to chemotherapeutic drugs/radiation and APL diagnosis. Future population-based studies examining childhood APL patterns and the potential association with specific environmental exposures and other risk factors are needed.

A Case of Acute Myeloid Leukemia (FAB M2) with Inversion 16 Who Presented with Pelvic Myeloid Sarcoma

Acute leukemias are the most common childhood cancer in all age groups. Acute myeloid leukemias (AML) constitute about 15–20% of acute leukemias. Fatigability, pallor, fever, and bleeding are the most common presenting symptoms of AML. Hepatosplenomegaly and lymphadenopathy are commonly encountered during physical examination. In rare instances eruptions due to skin involvement and localized tumor masses (myeloid sarcoma) may be found. Myeloid sarcoma is especially seen in AML-M2 subtype. By cytogenetic analysis, in AML-M2 subtype t(8;21) is often seen and it is more probable to find inversion 16 in AML-M4Eos subtype. Herein, we present a 15-year-old girl whose initial symptom was abdominal pain for three days and her pathological sign was a large abdominal mass which was verified by imaging studies and diagnosed as myeloid sarcoma by biopsy. On bone marrow examination, she had diagnosis of AML-M2 and by cytogenetic analysis inversion 16 was positive. She was treated with AML-BFM 2004 protocol and she is being followed up in remission on her ninth month of the maintenance therapy.

A single-center cytogenetic study of 629 Chinese patients with de novo acute myeloid leukemia--evidence of major ethnic differences and a high prevalence of acute promyelocytic leukemia in Chinese patients

Cytogenetic information is important in the diagnosis, classification, and prognostication of acute myeloid leukemia (AML). Data obtained from multicenter treatment trials are well published. In this study, we contribute cytogenetic data from a large series of 629 Chinese patients with de novo AML that were karyotyped in a single laboratory. A higher prevalence of acute promyelocytic leukemia was observed when compared with non-Chinese series. The difference was most prominent in the younger age group. Abnormalities at chromosomal region 11q23 and inv(16) seemed uncommon. These ethnic differences may indicate underlying genetic susceptibility to AML development and/or environmental differences. More comprehensive data on AML in the elder population are needed to assess the role of cytogenetics in predicting prognosis and guiding treatment in this large subgroup of patients.

Severe Eosinophilia in an infant with congenital acute myeloid leukemia with t(3;4;6)(q26;q25;q21): a case report

We report a case of acute myeloid leukemia with morphologic features of M7 according to the FAB (French-American-British) classification and severe eosinophilia in the peripheral blood and bone marrow at diagnosis. We consider it as congenital leukemia, as the symptoms started in the first month of life of the affected child. This case of leukemia is characterized by t(3;4;6)(q26;q25;q21) cytogenetic abnormality. The blasts in flow cytometry analysis expressed markers of megakaryocytic lineage along with expression of myeloperoxidase in 30% of them. This type of acute myelogenous leukemia with severe eosinophilia can be considered as a distinct clinicopathologic entity.

Banding and molecular cytogenetic studies detected a CBFB-MYH11 fusion gene that appeared as abnormal chromosomes 1 and 16 in a baby with acute myeloid leukemia FAB M4-Eo

The acute myeloid leukemia (AML) subtype M4Eo occurs in 5% of all AML cases and is usually associated with either an inv(16)(p13.1q22) or a t(16;16)(p13.1;q22) chromosomal abnormality. At the molecular level, these abnormalities generate a CBFB-MYH11 fusion gene. Patients with this genetic alteration are usually assigned to a low-risk group and thus receive standard chemotherapy. AML-M4Eo is rarely found in infants. We describe clinical, conventional banding, and molecular cytogenetic data for a 12-month-old baby with AML-M4Eo and a chimeric CBFB-MYH11 fusion gene masked by a novel rearrangement between chromosomes 1 and 16. This rearrangement characterizes a new type of inv(16)(p13.1q22) masked by a chromosome translocation.