Expression of cysteine protease inhibitors stefin A, stefin B, and cystatin C in human lung tumor tissue

Adv Exp Med Biol. 1997:421:259-65. doi: 10.1007/978-1-4757-9613-1_34.


In human lung tumor tissue specimen (n = 73) concentrations of stefins A and B were found to be increased 2.0-fold (p < 0.01) and 1.3-fold (p < 0.01), respectively, as compared to matched normal tissue. Stefin A and B concentrations were higher in primary tumors than in secondary tumors, i.e. metastases from other organs to the lung (p < 0.01; p < 0.05, respectively). Cystatin C concentrations were rather low and did not differ between tumor and normal tissue. Both concentrations of stefins did not correlate with TNM stages. Stefin A was higher in squamous cell carcinoma than in adenocarcinoma (p < 0.01), while stefin B did not show such a difference. At investigation of a relationship between survival probability of patients with primary tumors it was found that increased stefin B concentrations and total cysteine-protease-inhibitory activities but not stefin A concentrations were positively correlated with survival probability. It is concluded that stefins A and B are major contributors to the cysteine protease inhibitory activity in primary lung tumors. Stefin B proved to be a prognostic factor, especially in squamous cell carcinoma.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor*
  • Carcinoma, Squamous Cell / metabolism*
  • Carcinoma, Squamous Cell / physiopathology
  • Cystatin A
  • Cystatin B
  • Cystatin C
  • Cystatins / biosynthesis*
  • Cysteine Proteinase Inhibitors / biosynthesis*
  • Humans
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / physiopathology
  • Middle Aged
  • Prognosis


  • Biomarkers, Tumor
  • CST3 protein, human
  • CSTB protein, human
  • Cystatin A
  • Cystatin C
  • Cystatins
  • Cysteine Proteinase Inhibitors
  • CSTA protein, human
  • Cystatin B