[Cytosolic cathepsin D levels in squamous carcinomas of the lung].
OBJECTIVE
Cathepsin D is an aspartyl proteinase involved in tumoral invasion. The aim of this work was to study cathepsin D cytosolic levels in squamous carcinomas of the lung and their correlation with several clinical and biological parameters.


METHODS
The study group included 95 squamous lung carcinomas and 38 normal tissue samples from the same patients. Cathepsin D cytosolic concentrations were determined using an immunoradiometric assay (CIS BioInternational. France). EGFR, erbB2 protein, CD44s, CD44v5 and CD44v6 levels at cell surfaces were determined. The clinical stage, histological grade, ploidy and S-phase cellular fraction (SP) were also considered as variables of the study.


RESULTS
Cathepsin D cytosolic levels oscillated between 7.7 and 576 (median: 38.8) pmol/mg protein and were lower (p = 0.001) than those observed in 38 normal lung samples from the same patients. When tumors were classified according to different clinical and biological parameters, we noticed that cathepsin D levels were higher in carcinomas with lower proliferation rates and no nodal involvement, reaching statistical significance in both cases. Moreover, when lung carcinomas were classified according to cathepsin D concentrations, tumors with higher cathepsin D concentrations had lower EGFR levels (p = 0.011) and small global SP values (p = 0.025) and DNA index (p = 0.023). Likewise, they were found to be CD44s positive more frequently (p = 0.001) and SP positive less frequently (p = 0.022).


CONCLUSIONS
These results lead us to suggest the following: a) in squamous carcinomas of the lung, cathepsin D cytosolic levels are lower than those observed in normal lung samples from the same patients, and b) in this subtype of lung carcinomas, high cathepsin D levels are associated with tumors without nodal involvement, with low proliferation rates, lower EGFR levels, and a reduced positivity for CD44s, pointing to a possible role of this proteinase as a parameter of good outcome.
Ruibal
Alvaro
A
Laboratorio de Biología Tumoral FJD. Departamento de Medicina Nuclear. Fundación Jiménez Díaz. Madrid. España.
Núñez
Matilde Isabel
MI
Río
María del Carmen
Mdel C
García Díez
Susana
S
Rodríguez
Jesús
J
Alvarez de Linera
José Feliciano
JF
D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000473:pathology; D002402:Cathepsin D / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D066246:ErbB Receptors / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D015592:Immunoradiometric Assay; D008175:Lung Neoplasms / Q000201:enzymology* / Q000473:pathology; D008875:Middle Aged; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism
D002402:Cathepsin D; D066246:ErbB Receptors; D006023:Glycoproteins; D018960:Hyaluronan Receptors; D018719:Erb-b2 Receptor Tyrosine Kinases; C113800:CD44v5 antigen; C112697:CD44v6 antigen