Caveolin-1 expression in lung carcinoma varies according to tumour histotype and is acquired de novo in brain metastases.
OBJECTIVE
To study caveolin-1 (Cav-1) expression in metastatic lung carcinomas.


RESULTS
Cav-1 expression was investigated in a series of 121 lung carcinomas and it was shown that 18/121 tumours (14.9%) were Cav-1+. None of the pure bronchioloalveolar carcinomas proved to be positive, vs. 42.8% of the large cell carcinomas (neuroendocrine subtype excluded). Adenocarcinomas (8.5%), large cell neuroendocrine carcinomas (20%) and squamous cell carcinomas (29.6%) displayed an intermediate percentage of positive cases, suggesting a gradient of Cav-1 expression according to tumour histotype-related aggressiveness. Moreover, the percentage of Cav-1+ tumours with distant metastases was almost double that of non-metastatic tumours (17.8% vs. 8.1%), irrespective of the histotype. In 34 tumours metastatic to the brain, primary and secondary lesions were compared and 53% of brain metastases were Cav-1+ vs. 20.6% of primaries, indicating a de novo acquisition of Cav-1 expression. This pattern was exclusive to the brain, as it was not acquired in adrenal metastases. In our series, the presence of epidermal growth factor receptor amplification, determined by fluorescence in situ hybridization, was not related to Cav-1 reactivity.


CONCLUSIONS
Cav-1 immunoreactivity in lung carcinoma is histotype-dependent and acquired de novo in brain metastases, suggesting a site-specific phenotypic shift in secondary lesions.
Cassoni
Paola
P
Department of Biomedical Sciences & Oncology, University of Turin, Turin, Italy. paola.cassoni@unito.it
Daniele
Lorenzo
L
Maldi
Elena
E
Righi
Luisella
L
Tavaglione
Veronica
V
Novello
Silvia
S
Volante
Marco
M
Scagliotti
Giorgio Vittorio
GV
Papotti
Mauro
M
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D000310:Adrenal Gland Neoplasms / Q000378:metabolism / Q000556:secondary; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism* / Q000556:secondary; D018287:Carcinoma, Large Cell / Q000378:metabolism* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D004273:DNA, Neoplasm / Q000235:genetics; D018450:Disease Progression; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005784:Gene Amplification / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology
D014408:Biomarkers, Tumor; D051242:Caveolin 1; D004273:DNA, Neoplasm; C512478:EGFR protein, human; D066246:ErbB Receptors