Cyclooxygenase-2 expression in uveal melanoma: novel classification of mixed-cell-type tumours.
BACKGROUND
The expression of cyclooxygenase-2 (COX-2), an inducible prostaglandin (PG) synthase, has been investigated in various human malignant diseases, such as cutaneous melanoma. We investigated the expression of COX-2 in uveal melanoma and related the findings to prognostic factors.


METHODS
In 40 cases of uveal melanoma, immunostaining for COX-2 was done. COX-2 expression was related to histopathological prognostic markers, such as cell type, the presence of lymphocytic infiltration and vascular closed loops in the tumour, and cytomorphometry results.


RESULTS
COX-2 expression was found in 58% of the cases, and it correlated with markers of poor prognosis, such as epithelioid cell type and the presence of lymphocytic infiltration and vascular closed loops. The uveal melanomas expressing COX-2 had larger nuclei, as determined by cytomorphometry.


CONCLUSIONS
Whereas epithelioid tumours carry a worse prognosis than spindle cell tumours, until now it has not been possible to give a strong indication of prognosis in mixed-cell tumours. This study showed that mixed-cell tumours, representing the majority of uveal melanomas, may be further subclassified according to COX-2 expression, which serves as a marker of poor prognosis. The role of COX-2 in uveal melanoma should be further elucidated, and the use of COX-2 inhibitors warrants investigation as adjuvant treatment for this life-threatening malignant disease.
Figueiredo
Andresson
A
Henry C. Witelson Ophthalmic Pathology Laboratory and Registry, McGill University, Montreal, Que.
Caissie
Amanda L
AL
Callejo
Sonia A
SA
McLean
Ian W
IW
Gold
Phil
P
Burnier
Miguel N
MN
D014408:Biomarkers, Tumor / Q000378:metabolism; D002467:Cell Nucleus / Q000648:ultrastructure; D051546:Cyclooxygenase 2; D006801:Humans; D007158:Immunologic Techniques; D007527:Isoenzymes / Q000378:metabolism*; D008214:Lymphocytes / Q000473:pathology; D008545:Melanoma / Q000201:enzymology* / Q000473:pathology; D008565:Membrane Proteins; D008854:Microscopy, Electron; D011379:Prognosis; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D013194:Staining and Labeling; D014604:Uveal Neoplasms / Q000201:enzymology* / Q000473:pathology
D014408:Biomarkers, Tumor; D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases