[1799] Cathepsin K Expression in Benign Clear Cell “Sugar” Tumor of the Lung

S Gobbo, G Martignoni, M Pea, M Brunelli, M Chilosi, F Bonetti. University of Verona, Verona, Italy; Ospedale Orlandi, Bussolengo, Italy

Background: Cathepsin K is a papain-like cysteine protease that recently has been shown to be constantly, strongly and diffusely immunoexpressed in lymphangioleiomyomatosis. Lymphangioleiomyomatosis can be considered as part of the spectrum of proliferative lesions that have been previously defined under the name of “perivascular epithelioid cell tumours” (PEComas), including angiomyolipoma, clear-cell “sugar” tumour of the lung and extrapulmonary sites. The aim of this study is to evaluate Cathepsin K immunoexpression in clear-cell “sugar” tumour of the lung.
Design: We collected 3 clear-cell “sugar” tumours of the lung analysing the immunoexpression of cathepsin-k. We tested also Cathepsin K expression in 20 pulmonary adenocarcinomas, 20 squamous cell carcinomas of the lung and in 20 clear cell renal cell carcinomas.
Results: All the clear-cell “sugar” tumours were diffusely and strongly immunoreactive for cathepsin-k whereas none pulmonary adenocarcinoma, squamous cell carcinoma of the lung and clear cell renal cell carcinoma showed immunoreaction for this marker.
Conclusions: We demonstrated that: 1) Cathepsin K is constantly and strongly expressed in benign clear cell “sugar” tumor of the lung and can be useful in their differential diagnoisis with other primary and metastatic epithelial neoplasms of the lung. 2) The expression of Cathepsin K is an additional proof of the close relationship between benign clear cell “sugar” tumor and lymphangioleiomyomatosis of the lung.
Category: Pulmonary

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 258, Tuesday Afternoon


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