TDT

Terminal deoxynucleotidyl transferase (TDT) is a DNA polymerase without template, which catalyzes the insertion of free deoxyribonucleotides into the 3’-OH of DNA. TDT mainly exists in thymic precursor T cells and bone marrow precursor B cells. During the rearrangement of T cell receptor genes and immunoglobulin genes, it can add a random number of deoxyribonucleotides to enable different lymphocytes to recognize different antigens, thereby increasing the diversity of immune response. Lymphoblastic lymphoma/acute lymphoblastic leukemia (LBL/ALL) is a non-Hodgkin lymphoma originating from immature lymphocytes, and TDT, which can label precursor lymphocytes, has become an important diagnostic indicator for LBL/ALL. Moreover, some research found that patients with TDT negative expression have lower chemotherapy sensitivity and shorter overall survival, indicating that TDT has potential prognostic value. In addition, TDT can be expressed in some tumors such as thymoma, medulloblastoma, seminoma, Merkel cell tumor, and small cell lung cancer.