Abstract
Aims: This work was performed to study the expression of CD44v6 in several non-neoplastic and neoplastic thyroid lesions with special focus on its potential differential diagnostic value in differentiating between benign and malignant thyroid lesions and to evaluate its possible prognostic value in thyroid carcinoma
Methods and results: This study included 56 cases of thyroid lesions; eight of them were non-neoplastic lesion (2 cases normal typhoid tissues, 3 cases colloid nodular goiter, 3 cases Hashimoto’s thyroiditis, l0 cases follicular adenoma and 38 cases malignant neoplastic lesions; 18 cases papillary carcinoma; seven of them had lymph node metastasis, 15 cases follicular carcinoma, 2 cases medullary carcinoma and 3 cases undifferentiated carcinoma). All cases were formalin fixed, paraffin embedded tissues. Immunostaining was done using peroxidase labelled strepavidin-biotin technique to detect CD44v6. The case was considered positive if more than 50% of the aciner cells exhibit CD44v6 expression and it is evaluated as focal or diffuse membranous and/or cytoplasmic cellular immunoreactivity. No CD44 expression could be detected in normal thyroid tissues or in colloid nodular goiter whereas focal expression was detected in 1/3 (33.3%) cases of Hashimoto's thyroiditis. Therefore, non-neoplastic lesions showed CD44v6 expression in1/8 (12.5%) of cases. CD44v6 expression was detected in 3/10 (30%) of cases of benign neoplastic thyroid lesions; follicular adenoma. Cases of malignant neoplastic lesion displayed CD44v6 expression in 30/38 (78.9%) of cases. There is a significant statistical difference in CD44v6 expression between non neoplastic, benign neoplastic and malignant neoplastic lesions (P< 0.0001). Cases of papillary carcinoma, follicular carcinoma, medullary carcinoma and undifferentiated carcinoma showed positive CD44v6 immunoreactivity in 16/18 (88.9%), 11/15 (73.3%), 1/2 (50%) and 2/3 (66.7%) cases respectively. Cases of papillary carcinoma with lymph node metastasis revealed “diffuse” CD44v6 immunostaining in all the seven studied cases (100%), while 9/11 (81.8%) cases of papillary carcinoma without lymph node metastasis revealed CD44v6 immunostaining that was “diffuse” in 4/11 (36.3%) and this difference was statistically significant (p<0.02). A significant statistical difference (p< 0.03) was also detected between cases of CD44 positive follicular adenoma 3/10 (30%) and cases of CD44 positive follicular carcinoma 11/15 (73.3%). Conclusion: Our finding suggest that CD44v6 is a valuable marker in the differential diagnosis of non-neoplastic, benign neoplastic and malignant neoplastic lesions of thyroid, it can be used in the differentiation between follicular adenoma and follicular carcinoma and its diffuse expression serves as a biological marker for lymph node metastasis of papillary carcinoma