title: Monitoring therapy in canine malignant lymphoma and leukemia with serum thymidine kinase 1 activity--evaluation of a new, fully automated non-radiometric assay.
abstract: Thymidine kinase 1 (TK), which is involved in the synthesis of DNA precursors, is only expressed in S-G2 cells. Serum TK levels correlate to the proliferative activity of tumor disease. Determinations of TK levels have so far relied on radio enzyme assay (REA) and experimental ELISA methods, which have limited the clinical use of this biomarker, although recent studies in dogs with malignant lymphoma (ML) demonstrate its wide potential. A non-radiometric method based on a competitive immunoassay with specific anti-3'-azido-deoxythymidine monophosphate (AZTMP) antibodies has been further developed into the fully automated Liaison TK assay (DiaSorin). Sera from healthy dogs (n=30), and dogs with leukemia (LEUK) (n=35), ML (n=84), non-hematological tumors (n=50), and inflammatory disease (n=14) were tested using both methods. Lymphoma and LEUK samples were available before and during chemotherapy. The coefficients of variation for the Liaison TK assay in this study were 6.3 and 3.4% (low/high TK, respectively), and the correlation between TK REA (X) and the Liaison TK assay (Y) was y=0.9203x+1.3854 (R2=0.9501). The TK1 levels measured during chemotherapy gave very clear differences between dogs in complete remission and dogs out of remission. A Tukey-Kramer analysis showed that all LEUKs and MLs out of remission differed significantly from the other groups. The Liaison TK assay showed high precision, high sensitivity and a good correlation to the TK REA. The Liaison TK assay provides valuable clinical information in the treatment and management of canine LEUK and ML, with a potential to be further validated in human trials.
authors.affiliation: Center of Clinical Comparative Oncology, Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, and Uppsala University Hospital, Uppsala, Sweden. henrik.von.euler@kv.slu.se
authors.forename: Henrik P
authors.initials: HP
authors.lastname: Von Euler
authors.forename: Patricio
authors.initials: P
authors.lastname: Rivera
authors.forename: Anne-Charlotte
authors.initials: AC
authors.lastname: Aronsson
authors.forename: Christer
authors.initials: C
authors.lastname: Bengtsson
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Hansson
authors.forename: Staffan K
authors.initials: SK
authors.lastname: Eriksson
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002453:Cell Cycle; D004283:Dog Diseases / Q000188:drug therapy* / Q000473:pathology; D004285:Dogs; D007938:Leukemia / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D008223:Lymphoma / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D009369:Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D000091402:Prohibitins; D012074:Remission Induction; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; C000717331:PHB2 protein, human; D000091402:Prohibitins