title: Increased circulating normal and BCR-ABL+Ve progenitor numbers in Philadelphia chromosome-positive acute myeloid leukaemia.
abstract: We recorded elevated numbers of circulating myeloid and erythroid colony-forming cells in 15 adult patients with acute myeloid leukaemia (AML) who presented with high blood white cell counts. Since leukaemic blasts from three of these patients were Philadelphia chromosome-positive (Ph+), we were able to determine if blood progenitors from these particular patients arose from the leukaemic clone or from residual normal progenitors. Blasts and colonies were intensively investigated using a combination of cell surface marker analysis by flow cytometry, RT-PCR and interphase fluorescence in situ hybridization (FISH). FISH detected rearrangements within the major breakpoint BCR (M-BCR) region in blasts and in some myeloid and erythroid colonies from patients 1 and 2. The minor breakpoint (m-BCR) region was detected in blasts and in some myeloid and erythroid colonies from patient 3. RT-PCR detected long b2a2 BCR-ABL transcripts in blasts from patients 1 and 2, although misspliced short e1a2 transcripts were also seen in patient 1. Only e1a2 transcripts were found in blasts from patient 3. Flow sorting demonstrated the B-cell marker CD19 on blasts and on a proportion of myeloid and erythroid progenitors from patients 1 and 3. RT-PCR also detected IgH rearrangements, further evidence of B-cell differentiation, in blasts from these two patients. We conclude that both normal and clonal circulating progenitor numbers can be raised in both M-BCR and m-BCR Ph+ AML. The underlying cause, perhaps efflux from a congested marrow, may be common to AML patients with a high blood white cell count.
mesh_terms: D000208:Acute Disease; D000328:Adult; D014408:Biomarkers, Tumor; D016022:Case-Control Studies; D003114:Colony-Forming Units Assay; D004273:DNA, Neoplasm / Q000032:analysis; D015672:Erythroid Precursor Cells / Q000378:metabolism*; D005434:Flow Cytometry; D016044:Fusion Proteins, bcr-abl / Q000097:blood / Q000235:genetics*; D005803:Genes, Immunoglobulin / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000378:metabolism; D007958:Leukocyte Count; D023461:Myeloid Progenitor Cells / Q000378:metabolism*; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D051562:Proto-Oncogene Proteins c-bcr; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; C496613:BCR protein, human; D051562:Proto-Oncogene Proteins c-bcr