Minimally differentiated acute myeloid leukemia in Taiwan: predominantly occurs in children less than 3 years and adults between 51 and 70 years.
ABSTRACT Acute myeloid leukemia (AML) with minimal differentiation was usually referred to as acute undifferentiated leukemia in the past. With the help of immunophenotyping, this subtype of leukemia was shown to express myeloid antigens on the blasts and was designated AML-M0 by FAB Cooperative Study Group in 1991. Among the 423 consecutive newly diagnosed de novo AML at our institution, 12 (2.8%) were of M0 subtype. The proportion of M0 in AML was higher in children than in adults (8.2% vs 1.7%). Four other M0 patients referred from outside hospitals for immunophenotyping were also included in this study. There were two peaks in age distribution of these 16 patients: less than 3 years and between 51 and 70 years, respectively. Organomegaly was more common in patients with AML-M0 than in those with other subtypes (56.3% vs 29.2%, P = 0.025). The former patients had higher incidences of CD7 and CD34 expression on the leukemic cells than the latter ones (50% vs 16.9%, P = 0.003 and 69.2% vs 37.9%, P = 0.019, respectively). The patients with AML-M0 showed more frequent clonal chromosomal abnormalities in the leukemic cells than other AML patients (83.3% vs 53.9%, P = 0.039); the same is also true for complex cytogenetic aberrations (50% vs 11. 4%, P = 0.004). Adults with AML-M0 showed a lower complete remission (CR) rate and significantly poorer survival than those with non M0-AML. However there was no significant difference in outcome between the two groups of pediatric patients. In conclusion, AML-M0 is a unique subtype of leukemia that has distinct age distribution and shows different clinical and biological characteristics from other AML. Adult patients have poor prognosis. Whether pediatric patients had better outcome than adults needs to be clarified in further studies.
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ABSTRACT: To assess the impact of minimally differentiated acute myeloid leukemia (AML-M0) morphology in children, we analyzed 2 sequential Children's Cancer Group AML clinical trials. We compared presenting characteristics and outcomes of 82 CCG-2891 and CCG-2961 patients with de novo, non-Down syndrome (DS) AML-M0 with those of 1620 patients with non-M0 AML, and of 10 CCG-2891 patients with DS-associated AML-M0 with those of 179 with DS-associated non-M0 AML. Morphology and cytogenetics were centrally reviewed. The non-DS AML-M0 children had a lower white blood cell (WBC) count (P = .001) than their non-M0 counterparts and a higher incidence of chromosome 5 deletions (P = .002), nonconstitutional trisomy 21 (P = .027), and hypodiploidy (P = .002). Outcome analyses considering all children with non-DS AML demonstrated no significant differences between M0 and non-M0 patients. Analyses restricted to intensive-timing CCG-2891 and CCG-2961 demonstrated comparable complete response (CR) rates (79% and 78%) between non-DS M0 and non-M0 patients. Overall survival (OS) from diagnosis (38% +/- 14% versus 51% +/- 3%; P = .160) was not significantly different between the 2 groups. OS from end of induction (45% +/- 17% versus 63% +/- 3%; P = .038), event-free survival (EFS; 23% +/- 11% versus 41% +/- 3%; P = .018), and disease-free survival (DFS; 31% +/- 14% versus 52% +/- 3%; P = .009) were inferior in the M0 group. There was no significant outcome difference between DS-associated AML-M0 and non-M0 children. This study suggests that intensively treated non-DS-associated AML-M0 children have an inferior outcome compared with children with non-M0 AML.Blood 04/2007; 109(6):2314-21. · 9.06 Impact Factor
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ABSTRACT: Myeloid/natural killer (NK) cell precursor acute leukemia is an entity of acute leukemia characterized by poor prognosis and a CD7+CD56+ myeloid antigen+ phenotype without light-microscopic myeloperoxidase reactivity. This disease shares several clinical characteristics with acute myeloid leukemia (AML) M0. To clarify the relationship between these 2 leukemias, we analyzed 105 cases of AML M0. Among them, 17 were CD7+ and CD56+, 77 were negative for either antigen, and 11 could not be determined. CD7+CD56+ AML M0 showed onset at significantly lower patient age (median 46 versus 63 years, P = .004). The disease localization and the hematological manifestations were significantly different: CD7+CD56+ AML showed more frequent extramedullary involvement, fewer circulating leukemic blasts, less anemia, and less thrombocytopenia than did AML M0. The cytogenetic aberrations were also unique, because no 5q abnormalities were found in CD7+CD56+ M0. The prognosis of CD7+CD56+ M0 was poor in patients younger than 46 years (P = .03). Multivariate analysis showed that the CD7+CD56+ phenotype was a significant prognostic factor for AML M0, as well as age, circulating blast percentage, and chromosome 5 abnormalities These findings suggest that AML M0 consists of heterogeneous subgroups to be managed separately, and CD7+CD56+ M0 constitutes a distinct subtype of AML M0.International Journal of Hematology 07/2003; 77(5):482-9. · 1.68 Impact Factor
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ABSTRACT: The NOD/SCID human chimeric animal model was generated by implanting of human fetal bones (FBs) into subcutaneous sites of NOD/SCID mice (NOD/SCID-hu(+)), followed by inoculation of primary bone marrow mononuclear cells (BMNCs) obtained from patients with multiple myeloma (MM) into the FBs. The BMNCs from 30 patients with MM were inoculated, and 28 (93%) of them revealed evidence of tumor growth of myeloma cells (MCs) in the NOD/SCID-hu(+) mice. Intriguingly, 17 (61%) of the 28 patients' BMNCs inoculated developed not only myeloma in the bone marrow of the FBs, but also extramedullary macrotumors (EMTs) along the periosteum of the FBs. The tumor cells in these EMTs had plasmacytoid morphology and preserved antigens and cytogenetics similar, if not identical, to those in the parent MCs. Moreover, small tumor blocks from nine EMTs were transplanted into subcutaneous sites of subsequent recipient NOD/SCID mice without human FBs (NOD/SCID-hu(-)), and all but one grew successfully. Two of the EMTs have been maintained in the animal model for more than 12 months. The NOD/SCID-hu(+) chimeric animal model is highly efficient for growth of primary MCs and presents clinical features of human MM. The engrafted MCs can be maintained subsequently in NOD/SCID-hu(-) mice as in vivo culture.American Journal Of Pathology 03/2004; 164(2):747-56. · 4.52 Impact Factor