Terminal deoxynucleotidyl transferase activity in non-hematologic and hematologic neoplasms

The presence of terminal deoxynucleotidyl transferase (TdT) has been determined in neoplastic cells from 50 patients with non-hematologic tumors as well as neoplastic cells from 85 patients with hematologic malignancies. The results indicate that TdT is not present in cells from non-hematologic tumors, Hodgkin's lymphoma, B cell lymphoproliferative disorders, peripheral T cell neoplasms, reactive lymphadenopathy, and acute non-lymphocytic leukemia. In contrast, TdT activity is present in non-T non-B cell acute lymphocytic leukemia, T cell acute lymphocytic leukemia, T cell lymphoblastic lymphoma and chronic granulocytic leukemia in blast crisis. It is concluded that the TdT assay is a measurement useful in the differential diagnosis of some hematologic malignancies.