title: Pre-B-cell leukemia. A new phenotype of childhood lymphoblastic leukemia.
abstract: Large lymphoid cells containing small amounts of cytoplasmic IgM (clgM) but undetectable surface immunoglobulin (slg) have recently been recognized as precursors of B lymphocytes. They are a small, rapidly dividing pool of normal marrow lymphoblasts. Since lymphoblasts in most childhood acute lymphoblastic leukemias lack slg and other conventional B-lymphocyte and T-lymphocyte markers, we examined the possibility that some leukemias represent "pre-B"-cell neoplasms. In four of 22 consecutive patients, leukemic cells had the clgM+.slg- phenotype of pre-B cells. These patients' cells shared "common acute-lymphoblastic-leukemia" antigens and "B-cell" alloantigens, but differed in expression of several developmental features characteristic of the B-cell line. Pre-B-cell leukemias were readily responsive to chemotherapy. We conclude that a distinct subpopulation of previously unclassified leukemias reflects oncogenic transformation at the earliest recognizable stage in differentiation along the B-cell axis.
mesh_terms: D000293:Adolescent; D000951:Antigens, Neoplasm / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology* / Q000648:ultrastructure; D001853:Bone Marrow / Q000473:pathology; D002471:Cell Transformation, Neoplastic; D002648:Child; D002675:Child, Preschool; D003593:Cytoplasm / Q000276:immunology; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis; D007945:Leukemia, Lymphoid / Q000276:immunology / Q000473:pathology*; D008297:Male; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
chemical_list: D000951:Antigens, Neoplasm; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell; D004259:DNA-Directed DNA Polymerase