Serum miR-22 may be a biomarker for papillary thyroid cancer

The present study aimed to examine whether serum microRNA (miR)-22 may be considered a potential biomarker to differentiate patients with papillary thyroid cancer (PTC) from healthy controls. Reverse transcription-quantitative polymerase chain reaction demonstrated that serum miR-22 expression was significantly enhanced in patients with PTC compared with in patients with benign thyroid nodules (BTN) and healthy controls. The expression levels of miR-22 were also increased in the thyroid tissue of patients with PTC compared with in patients with BTN. In addition, increased miR-22 in the serum of patients with PTC was positively associated with metastasis. Furthermore, miR-22 serum levels were increased in patients with PTC and the B-Raf proto-oncogene, serine/threonine kinase V600E mutation. Meanwhile, compared with patients with PTC and ≤1 ng/ml thyroglobulin (Tg)-fine needle aspiration biopsy (FNAB), serum miR-22 was significantly enhanced in patients with PTC and 1–10 ng/ml Tg-FNAB and >10 ng/ml Tg-FNAB. A receiver operating characteristic analysis demonstrated that serum miR-22 distinguished patients with PTC from patients with BTN and healthy controls. In conclusion, to the best of our knowledge, the present study was the first to demonstrate that upregulation of serum miR-22 may be used as a potential biomarker to distinguish patients with PTC from healthy controls.