title: Nonpositive terminal deoxynucleotidyl transferase in pediatric precursor B-lymphoblastic leukemia.
abstract: Terminal deoxynucleotidyl transferase (TdT) is a unique intranuclear DNA polymerase that catalyzes the template-independent addition of deoxynucleotides to the 3'-hydroxyl terminus of oligonucleotide primers. The expression of TdT is restricted to lymphoid precursors. It is a useful marker in distinguishing acute lymphoblastic leukemia (ALL)from mature lymphoid neoplasms. Although TdT- T-cell ALL has been reported in the literature rarely, the frequency and significance of TdT-nonpositive (TdT(np) B-cell ALL have not been examined extensively. We reviewed the immunophenotypes of 186 new cases of pediatric B-cell ALL and found 5 TdT(np) cases (2.7%). They showed significantly higher frequencies of a WBC count of more than 50,000/microL (> 50.0 x 10(9)/L), CD10-, CD34-, and MLL gene rearrangement compared with those in TdT+ cases (3/5 [60%] vs 27/181 [14.9%], P = .03; 3/5 [60%] vs 11/181 [6.1%], P = .003; 4/5 [80%] vs 24/179 [13.4%], P = .002; 3/5 [60%] vs 9/181 [5.0%], P = .0019; respectively). These results indicate that nonpositive TdT does not rule out a diagnosis of ALL and suggest that TdT(np) B-cell ALL might be associated with CD10- and CD34- disease, a high WBC count, and MLL gene rearrangement.
authors.affiliation: Department of Pathology, University of Colorado School of Medicine, Denver, USA.
authors.forename: Lanting
authors.initials: L
authors.lastname: Liu
authors.forename: Loris
authors.initials: L
authors.lastname: McGavran
authors.forename: Mark A
authors.initials: MA
authors.lastname: Lovell
authors.forename: Qi
authors.initials: Q
authors.lastname: Wei
authors.forename: Bette A
authors.initials: BA
authors.lastname: Jamieson
authors.forename: Sara A
authors.initials: SA
authors.lastname: Williams
authors.forename: Norma N
authors.initials: NN
authors.lastname: Dirks
authors.forename: M Susan
authors.initials: MS
authors.lastname: Danielson
authors.forename: Lara M
authors.initials: LM
authors.lastname: Dubie
authors.forename: Xiayuan
authors.initials: X
authors.lastname: Liang
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D004253:DNA Nucleotidylexotransferase / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D015321:Gene Rearrangement; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008297:Male; D051788:Myeloid-Lymphoid Leukemia Protein; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis* / Q000235:genetics*; D011519:Proto-Oncogenes; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C497422:KMT2A protein, human; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase; D004253:DNA Nucleotidylexotransferase