COMBINED EXPRESSION OF CYTOKERATIN-17 AND THYROID PEROXIDASE IN BENIGN AND MALIGNANT THYROID NEOPLASMS’ PUNCTATES

Abstract

Summary. Aim: to conduct an immunocytochemical study of the joint expression of thyroid peroxidase (TPO) and cytokeratin-17 (CK-17) in punctates of benign and malignant thyroid neoplasms. Object and methods: immunocytochemical studies using monoclonal antibodies to TPO and CK-17 were performed on the material of fine-needle aspiration puncture biopsies of 23 benign and 28 malignant thyroid tumors, verified histologically, obtained from patients of both sexes aged 17 to 45 years. Statistical analysis was performed using the nonparametric Wald-Wolfowitz method. Results: in punctates of histologically verified benign thyroid tumors, TPO expression was detected in 73–100% of thyrocytes; CK-17 expression was absent in 91% of cases, and in 9% of cases, the content of CK-17⁺ cells of the follicular epithelium did not exceed 2%. At the same time, in punctates of malignant neoplasms, TPO expression was absent in 71.5% of cases; in 28.5% of cases, the number of TPO⁺ cells ranged from 2 to 50%. CK-17 expression was detected in 98% of thyrocytes and was absent in only 1 of 28 cases. A statistically significant difference in the expression index of CK-17 (p < 0.001) and in the expression index of TPO between benign tumors and papillary thyroid carcinomas (p < 0.001) was confirmed. Conclusions: for the first time, immunocytochemical detection of the combined expression of TPO and CK-17 in punctates of histologically verified benign and malignant thyroid tumors was performed. The absence of TPO expression and CK-17 expression in more than 2% of punctate thyrocytes indicates the malignancy of the neoplasms. The excess of TPO expression > 73% and the absence of CK-17 expression in punctate thyrocytes indicate the benignity of the thyroid neoplasms.