title: Terminal deoxynucleotidyl transferase-negative acute lymphoblastic leukemia.
abstract: OBJECTIVE
  Terminal deoxynucleotidyl transferase (TdT) is a useful marker in the diagnosis of acute lymphoblastic leukemia (ALL) (French-American-British [FAB] L1 and L2) and is most useful in distinguishing ALL from mature B-lymphoid neoplasms, such as Burkitt lymphoma (FAB L3) and other lymphoid malignancies. The frequency of TdT-negative ALL is not known. Here we report 3 TdT-negative ALL cases that met the criteria for T-cell ALL.
  
  
  METHODS
  We reviewed approximately 200 cases of ALL retrieved from the database at our institution. All cases were evaluated using Wright-Giemsa, myeloperoxidase, butyrate, and TdT staining; immunophenotyped using flow cytometry; and studied using Southern blot analyses for T-cell receptors and immunoglobulin gene rearrangement.
  
  
  RESULTS
  All ALL cases (L1 and L2) were TdT-positive, except for 3 cases that were of early T-cell lineage. None of the 3 cases demonstrated positivity for TdT in immunofluorescence staining with polyclonal antibodies or flow cytometry with monoclonal antibodies. Flow cytometric analysis confirmed a pre-T-cell immunophenotype in all 3 cases. One of the cases showed rearrangement of a T-cell antigen receptor and immunoglobulin heavy chain (J(H)). A second case showed germline configuration of T-cell receptors, but also showed rearrangement of the J(H), despite the expression of T-cell markers only.
authors.affiliation: Division of Pathology and Laboratory Medicine, Section of Hematopathology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: J
authors.initials: J
authors.lastname: Faber
authors.forename: H
authors.initials: H
authors.lastname: Kantarjian
authors.forename: M W
authors.initials: MW
authors.lastname: Roberts
authors.forename: M
authors.initials: M
authors.lastname: Keating
authors.forename: E
authors.initials: E
authors.lastname: Freireich
authors.forename: M
authors.initials: M
authors.lastname: Albitar
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism; D001853:Bone Marrow / Q000473:pathology*; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism*; D004273:DNA, Neoplasm / Q000032:analysis; D005434:Flow Cytometry; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000032:analysis; D016130:Immunophenotyping; D007223:Infant; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis* / Q000188:drug therapy / Q000201:enzymology; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D016896:Treatment Outcome
chemical_list: D015703:Antigens, CD; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D007143:Immunoglobulin Heavy Chains; D011948:Receptors, Antigen, T-Cell; D004253:DNA Nucleotidylexotransferase