Zelinskaya, A.     Immunocytochemical characteristics of thyrocytes in radioiodine refractory metastases of papillary thyroid cancer / A. Zelinskaya // Experimental Oncology. - 2019. - Том 41, N 4. - P342-345 Annotation: The aim of the work was to carry out an immunocytochemical (ICC) study of thyroid peroxidase (TPO) and thyroglobulin (Tg) expression in the punctates of the radioiodine (RI) refractory and RI uptake metastases of thyroid papillary carcinoma (PTC), on the basis of which it is possible to develop new methods of preoperative prediction of RI resistance and RI therapy efficiency for thyroid papillary carcinoma metastases. Materials and Methods: The ICC research was carried out on a fine needle aspiration biopsy material of 104 metastases that were found after thyroidectomy and RI therapy, i.e. in postoperative period (79 — radioiodine-refractory metastases, 25 — radioiodine-uptake metastases). The ICC analysis of TPO and Tg expression in PTC was performed with the use of monoclonal antibodies against TPO and Tg. Results: RI-refractory (RIRM) and RI-uptake metastases of PTC significantly differ by the percentage of cells expressing TPO and Tg (p 0.05, and p 0.05 respectively). The effectiveness of RI therapy was different for patients with different percentages of TPO-positive cells. Conclusion: A statistically significant difference was demonstrated in the expression of TPO in a punctates of RI-resistant and RI-sensitive metastatic TPC, based on which a new method for preoperative prediction of RI resistance and RI therapy efficiency was developed. It was shown that ICC determination of Tg expression in metastases is effective in preoperative monitoring of RI resistance of PTC if the part of Tg-positive cells in punctates is lower than 56%. The comprehensive study of the ICC profile of thyrocytes in RI-uptake metastases punctates allows us to develop a personified approach to prediction, monitoring and therapy of patients with PTC There are no free copies