Increased Incidence of TdT-negative Pre-B Acute Lymphoblastic Leukemia Associated With Poor Prognostic Features Among Mexican Children in Central Mexico

J Pediatr Hematol Oncol. 2024 Mar 1;46(2):e131-e136. doi: 10.1097/MPH.0000000000002802. Epub 2023 Dec 22.


Mexican and Hispanic children in Mexico and the United States, respectively, have the highest incidence and worst outcomes of pre-B acute lymphoblastic leukemia (ALL) compared with other racial/ethnic groups. Terminal deoxynucleotidyl transferase (TdT) is an intranuclear DNA polymerase normally present on immature lymphocytes (TdT-positive) and distinguishes ALL from mature lymphoid malignancies. We performed a multisite retrospective study to determine the incidence of TdT-negative precursor B-cell acute lymphoblastic leukemia (pre-B ALL) among Mexican, Caucasian, and US-born Hispanic children to correlate TdT expression with patient characteristics and known prognostic factors. Fisher exact test was performed for categorical variables and the Wilcoxon rank-sum test was used for continuous variables. TdT-negative pre-B ALL was most frequently identified in patients with National Cancer Institute high-risk disease ( P =0.014). TdT-negative expression was also most frequently associated with hypodiploid pre-B ALL ( P =0.001) and KMT2A gene rearrangement ( P =0.0012). Mexican children had the highest incidence of TdT-negative ALL compared with Caucasians and US Hispanics ( P <0.001), with an increased incidence of poor prognostic features as well. This study demonstrates significant differences in TdT-negative expression, genomic alterations, and leukemic ploidy based on race and ethnicity.

MeSH terms

  • Acute Disease
  • Child
  • DNA Nucleotidylexotransferase / metabolism
  • Humans
  • Incidence
  • Mexico / epidemiology
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma* / epidemiology
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma* / genetics
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma* / pathology
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma* / epidemiology
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma* / genetics
  • Prognosis
  • Retrospective Studies


  • DNA Nucleotidylexotransferase