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Cyclooxygenase-2 expression in primary and metastatic Merkel cell carcinoma
Zohar Joachims1, Raphael Feinmesser, Ofer Purim
1Department of Otolaryngology, Rabin Medical Center, Beilinson Hospital, Petah Tiqwa, Israel.
Abstract:
Cyclooxygenase-2 (COX-2) is involved in the development and progression of many tumors, and its inhibition has been shown to block tumor growth. This study examined COX-2 expression in primary and metastatic Merkel cell carcinoma (MCC). Formalin-fixed paraffin-embedded tissues from 26 primary MCCs and 7 lymph node metastases were stained immunohistochemically with a monoclonal antibody directed against COX-2, and the percentage and intensity of staining were analyzed semiquantitatively. Immunopositivity for COX-2 was found in 20 primary tumors (77%), and was diffuse in 16 of them (80%). Staining intensity was strong in 5 tumors (19%), moderate in 6 (23%), and weak in 9 (35%). Five metastases (71%) showed similar staining. Prominent mitotic activity was associated with more diffuse COX-2 immunopositivity. No association was found between COX-2 expression and outcome. This study confirms that most MCCs express COX-2 and shows that COX-2 expression is related to one parameter of aggressive behavior--a high mitotic rate--but not to any others. The possibility of treating MCC with COX-2 inhibitors should be considered.
Insights
Most Merkel cell carcinoma (MCC) tumors express cyclooxygenase-2 (COX-2), an enzyme linked to tumor growth. COX-2 expression correlates with higher mitotic rates in MCC, suggesting potential therapeutic targets.
Area of Science:
- Oncology
- Molecular Biology
- Immunohistochemistry
Background:
- Cyclooxygenase-2 (COX-2) plays a role in tumor development and progression.
- COX-2 inhibition can impede tumor growth.
- Merkel cell carcinoma (MCC) is an aggressive skin cancer where COX-2 involvement is under investigation.
Purpose of the Study:
- To investigate the expression of COX-2 in primary and metastatic Merkel cell carcinoma.
- To correlate COX-2 expression with clinicopathological features and patient outcomes.
Main Methods:
- Immunohistochemical staining of COX-2 in 26 primary MCCs and 7 lymph node metastases.
- Semiquantitative analysis of COX-2 staining percentage and intensity.
- Correlation analysis with mitotic activity and patient outcome.
Main Results:
- COX-2 immunopositivity was detected in 77% of primary MCCs and 71% of metastases.
- Diffuse COX-2 staining was observed in 80% of positive primary tumors.
- Strong, moderate, and weak staining intensities were noted.
- Higher COX-2 expression correlated with increased mitotic activity.
Conclusions:
- The majority of Merkel cell carcinomas express COX-2.
- COX-2 expression is associated with a higher mitotic rate, indicating aggressive behavior.
- Further consideration of COX-2 inhibitors for MCC treatment is warranted.
