[Prevalence of Cox2 marker in benign and malignant thyroid neoplasms with immunohistochemistry method]

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

[Evaluation of retinoblastoma expression in benign and malignant thyroid neoplasms]

Several factors are involved in the thyroid tumourigenic process. The role of Retinoblastoma [Rb] tumor suppressor gene mutation in thyroid carcinogenesis has been discussed. In this study we investigated the expression of Retinoblastoma gene in thyroid neoplasms and its association with clinical and histological findings, to evaluate its ability in distinguishing benign and malignant thyroid neoplasms and as a prognostic factor. The present cross sectional study investigated Avidin - Biotin immunohistochemistry using the Dako Rb - 1 clone in a series of 200 formalin - fixed, paraffin - embedded thyroid lesions, including 39 benign and 161 malignant neoplasms. Nuclear immunoreactivity in more than 10% of tumor cells was assessed as positive. Rb was positive in 74.2% of follicular adenoma, 87.5% of hurthle cell adenoma, 46.2% of papillary carcinoma, 66.7% of follicular carcinoma, 29.4% of medullary carcinoma and 50% of anaplastic carcinoma. Overall Rb nuclear immunoreactivity was observed in 76.9% of benign tumors and 45.9% of malignant lesions. No significant difference in Rb expression between follicular adenoma and follicular carcinoma was seen; also no association was found between Rb expression and invasiveness in malignant tumors. The results of this study indicate that Rb gene expression in benign thyroid tumors is significantly higher than in malignant ones [P=0.001], an association observed particularly in women. Rb gene inactivation is likely to play a role in malignant evolution of thyroid neoplasms and considering female predominance in thyroid tumors, Rb immunohistochemistry can potentially aid in the distinction between benign and malignant thyroid tumors in conjunction with morphology, but it is not helpful in differentiation between follicular adenoma and follicular carcinoma

[Expression of Nm23 marker in benign and malignant thyroid neoplasms immunohistochemical]

Several prognostic factors affect the outcome of thyroid carcinomas including tumor stage and distant metastases. Nm23 is a metastasis suppressor gene and has a crucial role in the control of metastatic potential of several carcinomas. The aim of our study is to evaluate expression of nm23 marker in benign and malignant thyroid neoplasms using the immunohistochemistry method and to elucidate its relationship with tumor size, vascular or capsular invasion and lymph node involvement. In a descriptive study, 200 paraffin blocks comprising of 38 benign and 162 malignant thyroid neoplasms stained with nm23 marker were studied. Cytoplasmic staining in more than 10% of cells was considered as positive. The relationship between nm23 and tumor size, vascular or capsular invasion, lymph node involvement was analysed using SPSS 11.5 software [p=0.05]. There was 40% positive incidence of nm23 in follicular adenoma, 87.5% in hurthle cell adenoma, 67.2% in papillary carcinoma, 66.7% in follicular carcinoma, and 64.7% in medullary carcinoma. In follicular adenoma, frequency of nm23 positive tumors was directly correlated to tumor size [p=0.04]. There are no statistically significant correlation between nm23 and tumor size, vascular or capsular invasion or lymph node involvement in malignant thyroid neoplasms. In papillary and medullary carcinoma, negative predictive value of nm23 for lymphnode involvement was over 80%. Also in follicular carcinoma, sensitivity and negative predictive value of nm23 for vascular invasion were approximately 90%. Lack of significant correlation between nm23 and tumor invasiveness [and probably metastasis] factors, demonstrate that although nm23 is a potentially metastasis suppressor gene, whereas in many other tumors it may play a different role in thyroid neoplasms, a role which necessitates further studies to be conducted