JUL 10, 2018 11:15 PM PDT

TdT Positive Cells - Not Just for Neoplasms

WRITTEN BY: Mauri Brueggeman

Terminal deoxyncleotidyl transferase (TdT) is a unique DNA polymerase molecule that is expressed by immature lymphoid cells, both normal and mutagenic.  As a cell ages, it loses the TdT expression capability.  Young lymph progenitor cells would be expected then to have this cell marker; cancerous lymph cells can be mutated versions of those young lymph progenitor cells growing out of control so increased TdT levels could be expected, and in fact have been used diagnostically in laboratory medicine.  TdT has been an identifiable marker since the late 1980s where it was found to be enhanced in acute undifferentiated leukemias, immature acute lymphoblastic leukemias, and in a fraction of cases of leukemic patients in blast crisis.  TdT acts by catalyzing the reaction that leads to the addition of deoxynucleotides to hydroxyl ends of oligonucleotides as part of DNA synthesis.  It also contributes to differences in antibody recognition sites by rearrangement of immunoglobulins or T-cell receptors.  It has long been associated with very undifferentiated neoplasms.

A new article published in the journal Human Pathology is a reminder that healthy lymph nodes and lymph cells can also express TdT because they are early lymphoid precursors; this is especially true in pediatric lymph nodes.  There are benign TdT positive lymph nodes in pediatric patients and this group focused on characterizing the presence of benign TdT positive cells and characterize the typical phenotype associated with their presence. 

Findings included that TdT was sparsely positive in all pediatric cases and in more than three quarters of adult lymph nodes evaluated (n=141).  It was noted that there was increased density of TdT positive cells in pediatric lymph nodes and TdT presence was not found to be associated with any clinical or histological factor other than identifying that these were lymphoid precursors with CD34 and CD10 also being expressed.

The study serves as a reminder to be mindful of the common phenotype of TdT positivity in early healthy lymphoid precursors and to carefully avoid misidentification of these cells as early neoplasm markers.

Sources: Human Pathology, International Journal of Biological Markers, American Journal of Clinical Pathology, Pathology Outlines,

About the Author
  • Mauri S. Brueggeman is a Medical Laboratory Scientist and Educator with a background in Cytogenetics and a Masters in Education from the University of Minnesota. She has worked in the clinical laboratory, taught at the University of Minnesota, and been in post secondary healthcare education administration. She is passionate about advances and leadership in science, medicine, and education.
You May Also Like
MAR 12, 2021
Drug Discovery & Development
Drug Starves Melanoma Tumors
MAR 12, 2021
Drug Starves Melanoma Tumors
Scientists at Sanford Burnham Prebys Medical Discovery Institute have identified a drug candidate that blocks the uptake ...
APR 11, 2021
Genetics & Genomics
Trial Shows Personalized Cancer Vaccines are Safe
APR 11, 2021
Trial Shows Personalized Cancer Vaccines are Safe
Vaccines are mostly known as tools to prevent illness. But cancer vaccines are a bit different, and aim to treat existin ...
MAY 05, 2021
Cancer
Developing Therapies to Combat Drug-Resistant Cell States
MAY 05, 2021
Developing Therapies to Combat Drug-Resistant Cell States
Drug resistant tumors present challenges in cancer treatment A significant challenge in the treatment of cancers is the ...
MAY 13, 2021
Immunology
Tumors Hide From the Immune System by Masquerading as Baby Cells
MAY 13, 2021
Tumors Hide From the Immune System by Masquerading as Baby Cells
The immune system is programmed to recognize foreign bodies as potentially dangerous, promptly removing them before the ...
MAY 10, 2021
Cancer
Advancements in nanotech pave the way for improved chemotherapy
MAY 10, 2021
Advancements in nanotech pave the way for improved chemotherapy
New research from Massachusetts General Hospital (MGH) reports on a development in improving the effectiveness of c ...
MAY 29, 2021
Cancer
New device detects skin cancer from tensile stiffness
MAY 29, 2021
New device detects skin cancer from tensile stiffness
A research team composed of scientists from City University of Hong Kong (CityU) has designed an automated non-invasive ...
Loading Comments...