Abstract: Background and purpose: Serum-thymidine kinase 1 (S-TK1) and macrophage inflammatory protein-1α (MIP-1α) are serum tumor markers, and their expression levels in serum are closely associated with disease severity and prognosis of thyroid cancer patient. Therefore, this article aimed to explore clinical value of the expression levels of S-TK1 and MIP-1α in the evaluation of postoperative radioactive  ¹³¹ I treatment for thyroid carcinoma. Methods: A total of 158 preoperative patients with thyroid cancer and 128 healthy subjects were selected as study group and control group. Serum MIP-1α and S-TK1 levels were compared between the two groups. All patients with malignancy were divided into groups: the successful group (58 cases) and the unsuccessful group (40 cases), the metastasis positive group (20 cases) and the metastasis negative group (78 cases). The levels of serum MIP-1α and S-TK1 were compared, and immunohistochemical staining technique was used to detect the expressions of MIP-1α and S-TK1 in the thyroid tissues of different groups of patients. The factors affecting postoperative outcome were analyzed by single factor and logistic regression analysis. Results: The expression levels of MIP-1α and S-TK1 were significantly higher in the thyroid malignant group than in the benign group and the healthy control group (P ＜ 0.05). Compared with those who were unsuccessful, the serum expression levels of MIP-1α and S-TK1 in the successful group before the  ¹³¹ I treatment were significantly reduced (P ＜ 0.05). The serum levels of MIP-1α and S-TK1 were significantly higher in the metastasis positive group than in the metastatic negative group (P ＜ 0.05). Immunohistochemical staining results showed that the positive expression rate of MIP-1α protein in the thyroid tissues of the malignant group (70.41%) was significantly higher than in the benign group (18.33%), and the positive expression rate of S-TK1 protein was significantly higher in the malignant group (68.37%) than in the benign group (15.00%) (P ＜ 0.05). Univariate analysis showed that maximum diameter, body mass index (BMI), thyroid-stimulating hormone (TSH), the expression levels of MIP- 1α and S-TK1 had significant effects on the first postoperative  ¹³¹ I clearing effect in patients with thyroid cancer (P ＜ 0.05). Logistic regression analysis showed the largest diameter of the lesion and the expression levels of TSH, MIP-1α and S-TK1 were independent factors influencing the efficacy of the first postoperative clearing effect (P ＜ 0.05). Conclusion: The expression levels of MIP-1α and S-TK1 are significantly higher in thyroid cancer patients than in healthy people. The expression levels of MIP-1α and S-TK1 are significantly increased after metastasis in thyroid cancer patients, and the maximum diameter of lesion, TSH and the expression levels of MIP-1α and S-TK1 are independent factors affecting the efficacy of the first postoperative clearing effect (P ＜ 0.05).

Key words: Thyroid cancer, Serum thymidine kinase 1, Macrophage inflammatory protein-1α, Curative effect evaluation