Abstract
Purpose::
Sebaceous carcinoma (SC) of the eyelid is a very unusual and aggressive neoplasm. The delay in the correct diagnosis combined with the lack of efficacious treatment options contributes to the observed poor prognosis for patients with this pathology. Consequently, a better understanding of the molecular mechanisms underlying SC carcinogenesis is needed to elucidate new methods and opportunities for improved therapies. Cyclooxygenase-2 (COX-2) is an enzyme that is induced in various cell types by oncogenes, mitogens, inflammatory cytokines, growth factors and UV radiation. Recently, it has been demonstrated that COX-2 is related to carcinogenic processes by converting pro-carcinogens to carcinogens, modulating inflammation and immune-suppression, stimulating tumor growth, inhibiting apoptosis, promoting angiogenesis and contributing to tumoral invasion and metastasis. Additionally, COX-2 expression has been extensively studied in several carcinomas such as Colorectal, Breast, Pancreas and Prostate. However, little is known about COX-2 expression in SC. The purpose of this study was to determine the expression of COX-2 in primary eyelid SC.
Methods::
34 formalin-fixed paraffin-embedded SC specimens were collected from The Henry C. Witelson Ophthalmic Pathology Laboratory - McGill University, Montreal, Canada. Immunohistochemical staining was performed in all cases using a monoclonal mouse antibody against COX-2 (Clone COX229). Two independent pathologists reviewed all slides to determine the intensity (weak, moderate or strong) and pattern (focal or diffuse) of the COX-2 expression. Diffuse expression was considered if more than 50% of the tumoral cells were positive.
Results::
29 specimens (85%) showed COX-2 positive staining. Within these 29 positive cases, strong staining was observed in fifteen (52%), moderate staining in eight (27%) and weak staining in six cases (21%). All positive cases but one showed a diffuse pattern of COX-2 expression.
Conclusions::
Most of the SC expressed COX-2 and revealed moderate/strong and diffuse expression for this marker. These findings suggest that future studies testing the applicability of anti-COX-2 medications as adjuvant treatments for this malignancy are warranted.
Keywords: eyelid • oncology • immunohistochemistry