**7. Poorly differentiated thyroid cancer and liquid biopsy**

Poorly differentiated thyroid carcinoma (PDTC) is malignant epithelial cell tumor derived from follicular cells that shows limited characteristics of follicular cell differentiation and is morphologically and behaviorally intermediate between differentiated thyroid carcinomas and anaplastic thyroid carcinoma [14]. miR-23 and miR-150 are downregulated, but miR-146b, miR-221, and miR-222 are upregulated in poorly differentiated thyroid cancer ensuring more aggressive behavior (**Table 5**).


**Table 5.** Expression of microRNA in PDTC.
