Activity of thymidine kinase as a prognostic marker of malignant proliferation in adolescents with lymphadenopathy.

Abstract

e19013 Background: Lymphadenopathy presents an important differential diagnostic problem. Thymidine kinase (TK) is an intracellular enzyme catalyzing the conversion of thymidine to thymidine monophosphate in the presence of adenosine triphosphate. TK is the product of certain genes for the progression from G1 through S phase. Determination of serum levels of the first TK isoenzyme is considered to have prognostic significance in malignant proliferation. TK increases significantly in the direct contact of malignant cells with biological fluids such as blood, lymph, or serous effusions, therefore its level changes most significantly in systemic blood diseases. Elevated serum TK has prognostic information and determines a high risk of tumor progression. The purpose of the study was to improve the accuracy of diagnosis of Hodgkin's lymphoma in adolescents, with its differentiation from lymphadenitis. Methods: The study included 34 patients: 13 – lymphadenitis, 21 – Hodgkin's lymphoma. Healthy donors served as a control group. Activity of TK1 (U/L) was determined in the blood serum by radioenzymatic method (in vitro) using a standard test system (Immunotech, BeckmanCoulter, Czech Republic). When TK1 activity was within 10.6-14.8 U/L, adenopathy of unclear etiology was considered lymphadenitis, and in 39.6-45 U/L – Hodgkin's lymphoma. Results: Activity of TK in the blood serum of patients with lymphadenitis (U/L) is shown in Table. Conclusions: Activity of thymidine kinase 1 can be measured as an objective marker for the proliferation of malignant cells, increasing the accuracy of Hodgkin's lymphoma diagnosis in adolescents.[Table: see text]