title: Terminal deoxynucleotidyl transferase expression can precede T cell receptor beta chain and gamma chain rearrangement in T cell acute lymphoblastic leukemia.
abstract: The nuclear enzyme terminal deoxynucleotidyl transferase (TdT) is thought to contribute to the diversity of certain immunoglobulin and T cell receptor gene rearrangements through the addition of random nucleotides at their variable (V)-joining (J) region junctions. An acute lymphoblastic leukemia (ALL) with an immature T cell phenotype (CD7+, CD5+, CD1+/-, CD2+/-, CD3-, CD4-, CD8-) was found to be TdT+ with germline immunoglobulin heavy chain, T cell receptor beta chain, and T cell gamma chain genes. The data indicate that TdT expression can precede T gamma and T beta rearrangement during T lymphoid ontogeny consistent with its proposed association with the T cell receptor rearrangement process. Southern analysis of certain cases of T-ALL may not result in the detection of a monoclonal population of cells.
mesh_terms: D000328:Adult; D000951:Antigens, Neoplasm / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D002454:Cell Differentiation; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism*; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D005796:Genes; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics; D007945:Leukemia, Lymphoid / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D011995:Recombination, Genetic; D013601:T-Lymphocytes / Q000201:enzymology / Q000473:pathology*
chemical_list: D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D004273:DNA, Neoplasm; D007136:Immunoglobulins; D011948:Receptors, Antigen, T-Cell; D004254:DNA Nucleotidyltransferases; D004253:DNA Nucleotidylexotransferase