title: Cathepsin K is selectively expressed in the stroma of lung adenocarcinoma but not in bronchioloalveolar carcinoma. A useful marker of invasive growth.
abstract: Lung bronchioalveolar carcinomas (BACs) are noninvasive tumors showing lepidic growth and excellent prognosis, whereas all the other variants of adenocarcinoma are invasive tumors with a worse prognosis. The identification of minimal invasive foci in adenocarcinoma, therefore, is of prognostic relevance. A series of 68 pulmonary tumors, including 40 acinar/papillary adenocarcinomas, 18 adenocarcinomas of the mixed subtype, and 10 BACs was tested by immunohistochemical analysis for cathepsin K expression, a proteinase involved in bone and extracellular matrix remodeling. Cathepsin K was produced by epithelial tumor cells in most invasive adenocarcinomas and, interestingly, by macrophages and fibroblasts in the stroma of invasive adenocarcinomas but not of BACs (P < .001). Our findings suggest pathogenetic implications of cathepsin K in the mechanisms of tumor invasiveness in lung carcinoma; in addition, cathepsin K immunodetection may be a valuable adjunct in the correct classification of pulmonary adenocarcinomas, especially in small sclerosing BACs and mixed adenocarcinoma subtypes with minimal infiltrative growth.
authors.affiliation: Department of Clinical and Biological Sciences, University of Turin and San Luigi Hospital, Orbassano, Torino, Italy.
authors.forename: Ida
authors.initials: I
authors.lastname: Rapa
authors.forename: Marco
authors.initials: M
authors.lastname: Volante
authors.forename: Susanna
authors.initials: S
authors.lastname: Cappia
authors.forename: Rosj
authors.initials: R
authors.lastname: Rosas
authors.forename: Giorgio V
authors.initials: GV
authors.lastname: Scagliotti
authors.forename: Mauro
authors.initials: M
authors.lastname: Papotti
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology* / Q000473:pathology; D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000201:enzymology* / Q000473:pathology; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D056657:Cathepsin K; D002403:Cathepsins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000201:enzymology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D011379:Prognosis; D017154:Stromal Cells / Q000201:enzymology
chemical_list: D014408:Biomarkers, Tumor; D002403:Cathepsins; C534130:CTSK protein, human; D056657:Cathepsin K