MicroRNA‑126 is downregulated in thyroid cancer cells, and regulates proliferation, migration and invasion by targeting CXCR4.

MicroRNA-126 (miR-126) has previously been reported to be downregulated in various types of cancer; however, at present, there are no studies of miR‑126 in human thyroid cancer. The present study aimed to determine the expression and effects of miR‑126 on thyroid cancer. The expression levels of miR‑126 were detected in human thyroid cancer tissues, matched normal adjacent tissues and human thyroid cancer cell lines using quantitative polymerase chain reaction. In addition, post‑transfection of human thyroid cancer cells with miR‑126 mimics, cell proliferation, migration and invasion assays, western blot analysis and luciferase assays were conducted. The results demonstrated that miR‑126 was downregulated in thyroid cancer tissues and cells. Furthermore, upregulation of miR‑126 inhibited cell proliferation, migration and invasion in thyroid cancer cells. The present study also provided evidence suggesting that miR‑126 may directly target C‑X‑C chemokine receptor type 4 (CXCR4) in thyroid cancer. These results indicated that miR‑126 may be investigated as a target for the treatment of thyroid cancer.