title: Analysis of thymidine kinase serum levels by novel method DiviTum in multiple myeloma and monoclonal gammopathy of undetermined significance - comparison with imaging methods 99mTc-MIBI scintigraphy and 18F-FDG PET/CT.
abstract: OBJECTIVE
  The study aimed at comparing two methods for evaluating thymidinekinase TK in serum - an older RIA method and novel DiviTum - in patients with MM and MGUS, and also comparing them with biochemical markers and degree of activity evaluated by imaging methods 99mTc-MIBI scintigraphy and 18F-FDG PET/CT.
  
  
  METHODS
  Serum thymidinekinase TK levels were evaluated by DiviTum and an RIA method (TK REA kit by Immunotech);The study analyzed correlation of TK activity in serum with biochemical markers reflecting activity of MM: β2-m, LDH, the ratio of kappa to lambda (κ/λ) free light chains and percentage of bone marrow plasma cells (BMPC). 99mTc-MIBI scintigraphy and 18F-FDG PET/CT were performed at the time of diagnosis. The degree of activity was expressed semiquantitatively. Scans were classified as 0 (normal activity), 1 (diffuse positivity) or 2 (focal positivity).
  
  
  RESULTS
  We found a strong positive correlation between TK in serum evaluated by DiviTum and by TK REA.. The DiviTum analytic method extended the detection range and was able to detect higher levels of TK than the RIA method. DiviTum technique found positive correlation with β2-m (r = 0.497) and LDH (r = 0.502) and moderate positive correlation with BMPC (r = 0.368). Significantly higher TK values measured by TK REA and DiviTum in the group of patients with MM (stages I, II or III) than in those with MGUS. Increased TK levels were observed in MIBI- or PET/CT-positive patients. Analysis of repeated measurements of TK in serum during treatment of MM patients found a correlation between change in TK measured by DiviTum and LDH during treatment.
  
  
  CONCLUSIONS
  Analysis revealed a significant correlation between TK in serum and LDH, β2-m and BMPC. Increased levels of TK in serum were observed in MIBI- or PET/CT-positive patients. Combination of positivity of imaging methods which can localize active tumor lesions and increased levels of TK in serum can have an impact on decision-making and optimization of the therapeutic approach.
authors.affiliation: Department of Internal Medicine III - Nephrology, Rheumatology and Endocrinology, University Hospital Olomouc, Czech Republic.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Bacovsky
authors.forename: Miroslav
authors.initials: M
authors.lastname: Myslivecek
authors.forename: Jiri
authors.initials: J
authors.lastname: Minarik
authors.forename: Vlastimil
authors.initials: V
authors.lastname: Scudla
authors.forename: Tomas
authors.initials: T
authors.lastname: Pika
authors.forename: Jana
authors.initials: J
authors.lastname: Zapletalova
authors.forename: Pavla
authors.initials: P
authors.lastname: Petrova
authors.forename: Margita
authors.initials: M
authors.lastname: Bartkova
authors.forename: Tomas
authors.initials: T
authors.lastname: Adam
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Gronowitz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000000981:diagnostic imaging / Q000201:enzymology*; D009101:Multiple Myeloma / Q000000981:diagnostic imaging / Q000201:enzymology*; D049268:Positron-Emission Tomography; D011379:Prognosis; D000091402:Prohibitins; D011863:Radioimmunoassay; D019275:Radiopharmaceuticals / Q000494:pharmacology; D013937:Thymidine Kinase / Q000097:blood*; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers; C000717331:PHB2 protein, human; D000091402:Prohibitins; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D013937:Thymidine Kinase