The translocation t(10,11)(p13;q14) resulting in the formation of the CALM/AF10 fusion gene is involved in various hematological malignancies including acute myeloid leukemia, T-cell acute lymphoblastic leukemia, and malignant lymphoma and is usually associated with poor prognosis. We established a knock-in mouse model allowing tissue-specific CALM/AF10 expression from the Rosa26 locus using a loxP-STOP-loxP cassette to study leukemic transformation by the CALM/AF10 fusion protein during hematopoiesis. vav-Cre induced pan-hematopoietic expression of the CALM/AF10 fusion gene led to acute leukemia with a median latency of 12 months. Leukemias were either myeloid or had myeloid feature and showed expression of the B cell marker B220. Gene expression profiling of leukemic bone marrow cells revealed the overexpression of Hoxa cluster genes and the Hox co-factor Meis1. The long latency to leukemia development suggested that additional, collaborative genetic lesions are required. We identified an average of 2 to 3 additional mutations per leukemia using whole-exome sequencing. When CALM/AF10 was expressed in the B lymphoid compartment using mb1-Cre or CD19-Cre inducer lines no leukemia development was observed. Our results indicate that CALM/AF10 needs to be expressed from the stem or early progenitor cell stage onward to permit the acquisition of additional mutations required for leukemic transformation.
The target cell of transformation is distinct from the leukemia stem cell in murine CALM/AF10 leukemia models.
Disease
View SamplesGlobal gene expression of 13 frozen samples, 6 from typical and 7 from atypical surgically resected primary lung carcinoids
Gene expression profiling reveals GC and CEACAM1 as new tools in the diagnosis of lung carcinoids.
Sex
View SamplesApproximately one third of acute myeloid leukemias (AMLs) are characterized by aberrant cytoplasmic localization of Nucleophosmin (NPMc+ AML), consequent to mutations in the NPM putative nucleolar localization signal. These events are mutually exclusive with the major AML-associated chromosomal rearrangements, and are frequently associated with normal karyotype, Fms-like tyrosine kinase (FLT3) mutations and multilineage involvement. We report the gene expression profiles of 78 de novo AMLs (72 with normal karyotype; 6 with non-major chromosomal abnormalities) that were characterized for the subcellular localization and mutation status of NPM. Unsupervised clustering clearly separated NPMc+ from NPMc- AMLs, regardless of the presence of FLT3 mutations or non-major chromosomal rearrangements, supporting the concept that NPMc+ AML represents a distinct entity. The molecular signature of NPMc+ AML includes up-regulation of several genes putatively involved in the maintenance of a stem cell phenotype, suggesting that NPMc+ AML may derive from a multipotent hematopoietic progenitor.
Acute myeloid leukemia bearing cytoplasmic nucleophosmin (NPMc+ AML) shows a distinct gene expression profile characterized by up-regulation of genes involved in stem-cell maintenance.
Specimen part
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