[Expression of microRNA-221 and IL-17 in papillary thyroid carcinoma and correlation with clinicopathologic features]

Objective: To study the expression of microRNA-221(miR-221) and IL-17 in papillary thyroid carcinoma (PTC) and their roles in the carcinogenesis of PTC. Methods: Real-time RT-PCR, Western blot and immunohistochemistry (IHC) were used to detect the expression of miR-221 and IL-17 in 40 cases of PTC, 20 adjacent normal thyroid tissues and 20 cases of nodular goiter, and the correlation with clinicopathologic features was analyzed. Results: (1)The expression level of miR-221 was significantly higher in PTC compared with nodular goiter and adjacent normal thyroid tissue (P<0.05), but not between the latter two (P>0.05). The expression of miR-221 was related to TNM staging, capsular invasion and lymph node metastasis (P<0.05) but not to patients' age, sex, tumor size, multifocality, tumor spread and vascular invasion.(2)Real-time RT-PCR and Western blot showed that higher levels of IL-17 mRNA and IL-17 protein in PTC than nodular goiter and adjacent normal thyroid tissue (P<0.05), but not between the latter two (P>0.05). IHC assay showed positive expression of IL-17 in PTC but not in nodular goiter and adjacent normal thyroid tissue. IL-17 expression was related to TNM staging, capsular invasion and lymph node metastasis, but not to patients' age, sex, tumor size, tumor spread and vascular invasion.(3) Expression analysis revealed a significant correlation between the miR-221 and IL-17 expression (r=0.524, P=0.001). Conclusions: The expressions of miR-221 and IL-17 are significantly higher and positively correlated in PTC, suggesting that miR-221 may regulate IL-17 expression by interacting with a variety of cytokines and inflammatory cells to participate in the development of PTC. miR-221 may be a potential novel prognostic indicator and therapeutic target for PTC.