The transformation from thyroid papillary carcinoma to anaplastic carcinoma point of view

Papillary thyroid carcinoma (PTC) is the most common type of thyroid neoplasm and generally well-behaved with favorable survival rates. However, a small subset of these well-differentiated tumors can unfortunately transform into anaplastic thyroid carcinoma (ATC) with highly aggressive behavior and dismal prognosis (1-4). As widespread adoption of next generation sequencing (NGS), a number of molecular alterations involved in this transition had been delineated. Previous studies supported the hypothesis that ATC might arise from dedifferentiation of preexisting PTC tumor stepwise (2,5,6). In consideration of their totally different outcomes, it is of utmost importance to recognize the rare aggressive PTC. In addition, more precise sub-classification and prognostic evaluation system of thyroid carcinoma need be established.