title: Early T cell differentiated chronic myeloid leukemia blast crisis with rearrangement of the breakpoint cluster region but not of the T cell receptor beta chain genes.
abstract: Early T cell differentiation is described in a case of Philadelphia chromosome-positive chronic myeloid leukemia (CML) in blast crisis, supporting multi-lineage differentiation potential of CML precursor cells. In the absence of myeloid markers, strong positivity for terminal deoxynucleotidyl transferase (TdT) and reactivity with T cell antibody 3A1, but lack of more mature T cell antigens, provided evidence for immature T cell differentiation. Molecular analysis of the breakpoint cluster region (bcr) in chromosome 22 revealed a rearrangement and thus confirmed the CML origin of the early T cell blasts. T cell receptor beta chain sequences were found in germline configuration and therefore suggest a very immature stage of T cell differentiation in the CML blasts.
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte; D000951:Antigens, Neoplasm / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D002454:Cell Differentiation; D002871:Chromosome Banding; D005260:Female; D005796:Genes; D006801:Humans; D007951:Leukemia, Myeloid / Q000235:genetics / Q000473:pathology*; D008875:Middle Aged; D010677:Philadelphia Chromosome; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000502:physiology; D014178:Translocation, Genetic
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D011948:Receptors, Antigen, T-Cell