ABSTRACT
There are different prognostic factors in thyroid neoplasms. Cox2 is an enzyme which plays a role in the synthesis of prostaglandin. Increased expression of Cox2 has been reported in different kinds of cancers such as colorectal, stomach, lung, prostate, breast and thyroid. Thyroid malignancies are among the common malignancies of the endocrine system, and various molecular studies are being performed to determine their pathogenesis. To study the prevalence of Cox2 in malignant and benign neoplasms of the thyroid and its relationship with other clinical and pathological factors, we analyzed 200 paraffin blocks including 137 thyroid papillary carcinoma, 10 thyroid follicular carcinoma, 17 thyroid medullary carcinoma, 2 anaplastic cases, 27 thyroid follicular adenoma, 7 thyroid Hurthle cell adenoma using the immiunohistochemistry method for the Cox2 enzyme marker. Positive results obtained for cases Cox2 were 38.7% thyroid papillary carcinoma, 20% follicular carcinoma, 29.6% medullary carcinoma, 25.9% follicular adenoma, 28.5% hurthle cell adenoma. Statistical analysis showed no significant difference among various groups of thyroid neoplasms and expression of Cox2. Also, no relationship between vascular, lymphatic and capsule invasion and expression of Cox2 in malignant and benign neoplasms of the thyroid was found. It appears that Cox2 is not a suitable marker to distinguish between different types of thyroid neoplasm