title: Serum Thymidine Kinase 1 Activity Following Nephrectomy for Renal Cell Carcinoma and Radiofrequency Ablation of Metastases to Lung and Liver.
abstract: OBJECTIVE
  Thymidine kinase 1 (TK1) is involved in DNA synthesis and is considered a reliable and sensitive marker of cell proliferation. The aim of this study was to investigate the prognostic value of measurements of serum TK1 activity following tumor ablation.
  
  
  METHODS
  This study was performed on 32 patients with renal cell carcinoma (RCC) who had undergone nephrectomy and 35 patients with cancer of different histology with metastases to the liver (n=28) and lung (n=7) treated with radiofrequency ablation (RFA). The TK1 activity was measured with DiviTum (Biovica) immunoassay.
  
  
  RESULTS
  In patients with RCC with no evidence of disease during their observation, a significant decrease of the TK1 activity was observed on the day following nephrectomy (p<0.0001). The mean calculated half-life ±SEM was 10.8±1.2 h. Taking into account the short half-life, measurements of TK1 were performed 24 h after nephrectomy or RFA of metastases. It was found that elevated TK1 activity (>60 Du/l) on the day after nephrectomy independently predicted poor recurrence-free survival (hazard ratio=5.0, p=0.040), after adjustment for T-stage, age and pretreatment TK1. Patients scheduled for RFA averaged 1.4 lesions and an average lesion diameter of 2.2 cm. Multivariate Cox's regression model demonstrated the significant association of any increase of TK1 activity or decrease not reaching ≤60 Du/l on the day after ablation with poor progression-free survival (hazard ratio=4.6, p=0.001), after adjustment for the type of primary tumor, the number and size of metastases.
  
  
  CONCLUSIONS
  The half-life for serum TK1 activity is 10.8±1.2 h. The measurements of TK1 activity following nephrectomy or RFA of metastases could be an important tool in prognostic evaluation.
authors.affiliation: Department of Oncology, Hadassah and Hebrew University Medical Center, Jerusalem, Israel nisman@hadassah.org.il.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Nisman
authors.affiliation: Department of Radiology, Hadassah and Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Liat
authors.initials: L
authors.lastname: Appelbaum
authors.affiliation: Department of Urology, Hadassah and Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Yutkin
authors.affiliation: Department of Oncology, Hadassah and Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Hovav
authors.initials: H
authors.lastname: Nechushtan
authors.affiliation: Department of Oncology, Hadassah and Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Ayala
authors.initials: A
authors.lastname: Hubert
authors.affiliation: Department of Radiology, Hadassah and Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Uziely
authors.affiliation: Department of Urology, Hadassah and Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Dov
authors.initials: D
authors.lastname: Pode
authors.affiliation: Department of Oncology, Hadassah and Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Peretz
mesh_terms: D000368:Aged; D002292:Carcinoma, Renal Cell / Q000097:blood* / Q000473:pathology / Q000601:surgery; D017115:Catheter Ablation; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000097:blood* / Q000473:pathology / Q000601:surgery; D008113:Liver Neoplasms / Q000097:blood* / Q000556:secondary / Q000601:surgery; D008175:Lung Neoplasms / Q000097:blood* / Q000556:secondary / Q000601:surgery; D008297:Male; D009392:Nephrectomy; D013937:Thymidine Kinase / Q000097:blood*
chemical_list: D013937:Thymidine Kinase; C092717:thymidine kinase 1
keywords: TK1 activity; half-life; nephrectomy; prognosis; radiofrequency ablation