Abstract
Abstract: :
Purpose:Sebaceous cell carcinoma (SeCC) is the second most common malignant eyelid tumor, accounting for 1 to 5.5% of all eyelid cancers. SeCC is highly aggressive, with considerable metastatic potential, and a significant mortality rate. SeCC often displays an intra-epithelial pattern of invasion that is referred to as pagetoid spread due to its similarity to the invasion pattern of ductal breast carcinoma in Paget disease. The expression of COX-2, a prostaglandin synthetase, may facilitate several oncogenic processes, including tumor invasion, angiogenesis, and metastasis. Increased COX-2 expression, induced by factors such as oncogenes, growth factors, and cytokines, has been reported in ductal breast carcinoma. Due to the similarities between mammary and sebaceous glands, the aim of this study is to investigate the immune-expression of COX-2 in non-neoplastic sebaceous glands and SeCC, in an effort to understand the highly aggressive nature of SeCC. Methods:Twelve cases of SeCC were collected from the Henry C. Witelson Eye Pathology Laboratory and Registry, Montreal, Canada. Formalin-fixed, paraffin-embedded specimens were immunostained with a monoclonal antibody against COX-2. The intensity of COX-2 expression was recorded as either 0, + or ++ in tumor cells as well as non-neoplastic sebaceous glands surrouding the tumor area. Results:Five out of 12 SeCC cases demonstrated COX-2 positivity (++) while the remaining seven cases were COX-2 negative. It was observed that COX-2 staining was most intense in the vicinity of lipid-rich, vacuolated cells. Pagetoid spread was found to be COX-2 positive in 3 of 9 cases showing this invasive pattern. In six cases, non-neoplastic sebaceous glands were present and 4 of these cases showed COX-2 expression in these glands. Conclusion:Intense COX-2 expression was found in the majority of non-neoplastic sebaceous glands as well as nearly half of the sebaceous cell carcinoma cases. COX-2 expression in non-neoplastic sebaceous glands may represent inflammation, or alternatively may be an early marker for neoplastic transformation. COX-2 expression in sebaceous cell carcinoma may explain the aggressiveness of this lethal malignancy.
Keywords: 507 pathology: human • 434 immunohistochemistry • 496 oncology