Cyclooxygenase-2 expression in primary Merkel cell carcinoma.
BACKGROUND
Merkel cell carcinoma (MCC) is a highly malignant neuroendocrine skin tumor. The typical course of MCC is rapid progression of the primary tumor and metastatic dissemination to the regional lymph nodes. Thus far, no biological, prognostic marker has been established for this aggressive neoplasm. Cyclooxygenase-2 (Cox-2) is undetectable in most normal tissues, but it is induced in various cell types by inflammation and carcinogenesis. Although the expression and function of Cox-2 have been studied extensively in several carcinomas, little is known about Cox-2 expression in neuroendocrine carcinomas. The aim of the present report was to study Cox-2 expression in MCC and find out whether this expression correlates with outcome.


METHODS
Immunohistochemical analysis for Cox-2 was performed on 22 primary MCC samples.


RESULTS
Almost 70% of the samples showed positive staining. Protein expression of Cox-2 was sparse and low in intensity. We found a tendency for enhanced Cox-2 expression in tumors located in sun-exposed areas. Cox-2 expression had no significant statistical correlation with clinical parameters.


CONCLUSIONS
MCC expresses Cox-2 in low levels, and the expression did not prove to be a prognostic factor. Furthermore, the low expression suggests that the primary treatment option for MCC is not therapeutic inhibition of Cox-2.
Koljonen
Virve
V
Department of Plastic Surgery, Helsinki University Hospital, Helsinki University, Helsinki, Finland. virve.koljonen@hus.fi
Lassus
Patrik
P
Tukiainen
Erkki
E
Ristimäki
Ari
A
Haglund
Caj
C
Böhling
Tom
T
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D015266:Carcinoma, Merkel Cell / Q000201:enzymology* / Q000556:secondary / Q000601:surgery; D051546:Cyclooxygenase 2; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000201:enzymology / Q000473:pathology; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012878:Skin Neoplasms / Q000201:enzymology* / Q000473:pathology / Q000601:surgery
D014408:Biomarkers, Tumor; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases