title: Stefin a and stefin B: markers for prognosis in operable squamous cell carcinoma of the head and neck.
abstract: OBJECTIVE
  The aim of this study was to test the hypothesis about the protective role of high stefin A and stefin B concentrations in operable carcinoma of the head and neck.
  
  
  METHODS
  Stefins A and B concentrations were measured in tissue cytosols of nontumorous mucosa and primary tumors from 92 patients. For quantitative analysis of stefins in tumor cytosols, commercially available enzyme-linked immunosorbent assays were used.
  
  
  RESULTS
  Stefin A was upregulated in 53 patients (higher concentrations were measured in tumor samples than in nontumorous mucosa) and was downregulated in 39 patients. The corresponding numbers for stefin B were 49 and 43, respectively. A significantly higher proportion of downregulated cases were found among patients with disease re-appearance. In the Cox model, high stefin A concentrations appeared as independent predictors for favorable disease-free survival. Assuming a "broken stick" model, a significant increase in the recurrence rate after the threshold of 1063 ng/mgp (the 64th percentile in the group) was found, the hazard ratio reaching 3% of the reference value with doubling of the level of stefin A. These results were reconfirmed after pooling the data with two historical data sets into a uniform series involving 182 patients.
  
  
  CONCLUSIONS
  A group of patients at high risk for disease progression was identified, characterized by the downregulated stefin A protein in the tumor compared with the nontumorous mucosa. Stefin A was recognized as a promising candidate marker for prognosis in patients with operable carcinoma of the head and neck.
authors.affiliation: Department of Radiotherapy, Institute of Oncology, Ljubljana, Slovenia. pstrojan@onko-i.si
authors.forename: Primoz
authors.initials: P
authors.lastname: Strojan
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Anicin
authors.forename: Branka
authors.initials: B
authors.lastname: Svetic
authors.forename: Maja
authors.initials: M
authors.lastname: Pohar
authors.forename: Lojze
authors.initials: L
authors.lastname: Smid
authors.forename: Janko
authors.initials: J
authors.lastname: Kos
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000097:blood* / Q000532:radiotherapy / Q000601:surgery; D055312:Cystatin A; D055313:Cystatin B; D015891:Cystatins / Q000097:blood*; D005260:Female; D006258:Head and Neck Neoplasms / Q000097:blood* / Q000532:radiotherapy / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood*; D011379:Prognosis; D011446:Prospective Studies; D018709:Statistics, Nonparametric
chemical_list: C524994:CSTB protein, human; D055312:Cystatin A; D015891:Cystatins; D009363:Neoplasm Proteins; C026407:CSTA protein, human; D055313:Cystatin B