RESUMO
Objective: To investigate the relationship between interleukin-6 (IL-6) and papillary thyroid carcinoma (PTC), and to elucidate the role of IL-6 in the occurrence and development of PTC and its possible mechanism Methods: The serum levels of IL-6 were measured by ELISA method in 5 patients with PTC (case 1 group), 5 patients with Hashimoto thyroiditis (HT) complicated with PTC (case 2 group) and 5 normal persons (normal group). The thyroid tissues of 20 patients with PTC (PTC group), 15 patients with HT complicated with PTC (HT +PTC group) and 18 normal persons (control group) were collected. The positive expression rates of IL-6, IL-6 receptor (IL-6R), nuclear factor kappa-B (NF-κB) and RET/PTC proteins in thyroid tissue of the subjects in various groups were detected by immunohistochemistry (IHC) method; the relationships between IL-6, IL-6R and NF-kB, RET/PTC expressions were analyzed. Results: In the patients with PTC, the complex papillary hyperplasia of thyroid epithelial cells accompanying with ground glass like nuclei and nuclear sulcus and inclusions were seen; in the patients with HT complicated with PTC, in addition to the typical pathological changes of PTC, the diffuse lymphoid tissue infiltration accompanying with lymphoid follicle formation, and the coexistence of hyperplasia and atrophic thyroid follicular epithelium with eosinophic degeneration of thyroid epithelium and interstitial fibrosis were also found. The lobular structrure of normal thyroid tissue was found, and the follicular cells were in the same size The ELISA results showed that the serum IL-6 levels of the patients in PTC group and HT+ PTC group were higher than those in normal group (P<0. 05); the IHC results showed that the positive expression rates of IL-6, IL-6R, NF-κB, and RET/PTC in thyroid tissue of the patients in PTC group were higher than those in control group (P<0. 05). The expressions of IL-6, and IL-6R were positively correlated with the expressions of NF-kB and RET/PTC protein (P<0. 05). Conclusion: IL-6 may be involved in the occurrence and development of PTC through the RET/PTC-NF-B signal pathway.