Considering that both FTC and PTC are differentiated thyroid carcinomas originating from a common cell type (the follicular cell), the upregulation of miR-221 and miR-222 in MI-FTC may lead to dysregulated cell cycle progression by targeting CDKN1B and CDKN1C and facilitates its hematogenous metastasis to lung and bone. This evidence concerns the gene CDKN1C and thyroid gland carcinoma.