Increased expression of miR-221 and miR-222 in patients with thyroid carcinoma

Abstract

To determine the diagnostic significance of miR-221 and miR-222 expression in papillary thyroid carcinoma and the associations with clinicopathological features of patients, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed in 83 cases of papillary thyroid carcinoma and the corresponding normal tissues, as well as in 25 cases of multinodular goiters and 15 cases of normal thyroid tissues. Expression of two miRNAs was then associated with patient clinicopathological features. After that receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic values of miR-221 and miR-222 in papillary thyroid carcinoma. These results demonstrate that both mir-221 and miR-222 were significantly over-expressed in papillary thyroid carcinoma compared to non-tumor tissues. ROC curves indicated a sensitivity and specificity of 80.7 and 74.8%, respectively for miR-221 and 78.3 and 83.2%, respectively for mir-222. Moreover, expression of miR-221 and miR-222 was significantly associated with extrathyroidal invasion of papillary thyroid carcinoma (p = 0.027 and 0.034, respectively) with a sensitivity of 63.6 and 63.6% and the specificity of 52.5, 73.8%, respectively. Expression of both miRNAs was correlated in papillary thyroid carcinomas (r = 0.468, p = 0.000), which suggested that expression of both miR-221 and miR-222 might be used as tumor markers for diagnosis and prediction of tumor progression. Key words: Thyroid cancer, goiters, miRNA, diagnosis, qRT-PCR.