title: A novel leukemia cell line, MR-87, with positive Philadelphia chromosome and negative breakpoint cluster region rearrangement coexpressing myeloid and early B-cell markers.
abstract: We developed a Philadelphia chromosome (Ph) positive cell line, designated MR-87, from a 4-year-old boy with Ph+-acute leukemia. MR-87 cells grew in single cell suspensions with a doubling time of 120 to 144 hours. Both MR-87 and original leukemia cells were positive for myeloperoxidase (MPO) and myeloid antigen CD13. These cells exhibited the early B-cell phenotype, ie, terminal deoxynucleotidyl transferase+, Ia+, CD19+, and CD10+. Rearrangement of the immunoglobulin heavy chain was confirmed in both. Approximately 80% of MR-87 cells coexpressed CD13 and lymphoid antigens CD10 or CD19, as confirmed by a two-color analysis. Simultaneous expression of MPO and CD19 on a single MR-87 cell was demonstrated at ultrastructural level. Thus, MR-87 is a Ph+ leukemia cell line exhibiting a hybrid phenotype. The breakpoint cluster region (bcr) was not rearranged in the MR-87 cells and subsequent analysis using antisera revealed that these cells expressed a novel protein, P190c-abl, which was immunoprecipitated with anti-abl and anti-phosphotyrosine antibodies. The MR-87 line will be most useful for investigating the biology and pathogenesis of Ph+ bcr- acute leukemia.
mesh_terms: D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000032:analysis / Q000145:classification*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001853:Bone Marrow / Q000032:analysis / Q000473:pathology*; D002460:Cell Line; D002675:Child, Preschool; D015321:Gene Rearrangement; D006651:Histocytochemistry; D006801:Humans; D007150:Immunohistochemistry; D007621:Karyotyping; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000473:pathology; D008297:Male; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000302:isolation & purification; D016315:Proto-Oncogene Proteins c-abl; D014178:Translocation, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D014408:Biomarkers, Tumor; D011518:Proto-Oncogene Proteins; D016315:Proto-Oncogene Proteins c-abl