No abstract

Current sources of stem cells include embryonic stem cells (ESCs) and adult stem cells (ASCs). However, concerns exist with either source: ESCs, with their significant ethical considerations, tumorigenicity, and paucity of cell lines; and ASCs, which are possibly more limited in potential. Thus, the search continues for an ethically conducive, easily accessible, and high-yielding source of stem cells. We have isolated a population of multipotent cells from the human term placenta, a temporary organ with fetal contributions that is discarded postpartum. These placenta-derived multipotent cells (PDMCs) exhibit many markers common to mesenchymal stem cells-including CD105/endoglin/SH-2, SH-3, and SH-4-and they lack hematopoietic-, endothelial-, and trophoblastic-specific cell markers. In addition, PDMCs exhibit ESC surface markers of SSEA-4, TRA-1-61, and TRA-1-80. Adipogenic, osteogenic, and neurogenic differentiation were achieved after culturing under the appropriate conditions. PDMCs could provide an ethically uncontroversial and easily accessible source of multipotent cells for future experimental and clinical applications. Stem Cells 2005;23:3-9

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DNMT3A mutations are associated with poor prognosis in acute myeloid leukemia (AML), but the stability of this mutation during the clinical course remains unclear. In the present study of 500 patients with de novo AML, DNMT3A mutations were identified in 14% of total patients and in 22.9% of AML patients with normal karyotype. DNMT3A mutations were positively associated with older age, higher WBC and platelet counts, intermediate-risk and normal cytogenetics, FLT3 internal tandem duplication, and NPM1, PTPN11, and IDH2 mutations, but were negatively associated with CEBPA mutations. Multivariate analysis demonstrated that the DNMT3A mutation was an independent poor prognostic factor for overall survival and relapse-free survival in total patients and also in normokaryotype group. A scoring system incorporating the DNMT3A mutation and 8 other prognostic factors, including age, WBC count, cytogenetics, and gene mutations, into survival analysis was very useful in stratifying AML patients into different prognostic groups (P < .001). Sequential study of 138 patients during the clinical course showed that DNMT3A mutations were stable during AML evolution. In conclusion, DNMT3A mutations are associated with distinct clinical and biologic features and poor prognosis in de novo AML patients. Furthermore, the DNMT3A mutation may be a potential biomarker for monitoring of minimal residual disease. (Blood. 2012;119(2):559-568)

Mutations in the additional sex comb-like 1 (ASXL1) gene were recently shown in various myeloid malignancies, but they have not been comprehensively investigated in acute myeloid leukemia (AML). In this study, we analyzed ASXL1 mutations in exon 12 in 501 adults with de novo AML. ASXL1 mutations were detected in 54 patients (10.8%), 8.9% among those with normal karyotype and 12.9% among those with abnormal cytogenetics. The mutation was closely associated with older age, male sex, isolated trisomy 8, RUNX1 mutation, and expression of human leukocyte antigen-DR and CD34, but inversely associated with t(15;17), complex cytogenetics, FLT3-internal tandem duplication, NPM1 mutations, WT1 mutations, and expression of CD33 and CD15. Patients with ASXL1 mutations had a shorter overall survival than patients without, but the mutation was not an independent adverse prognostic factor in multivariate analysis. Sequential analyses showed that the original ASXL1 mutations were lost at relapse and/or refractory status in 2 of the 6 relapsed ASXL1-mutated patients studied, whereas 2 of the 109 ASXL1-wild patients acquired a novel ASXL1 mutation at relapse. In con