This study aimed to clarify the mechanisms induced by HDACi in in vitro models of thyroid cancer, highlighting the ability of these compounds to induce re-differentiation in thyroid cancer cell lines via the over-expression of NIS, the modulation of the long non-coding RNA H19, and the suppression of oncogenes, like TTF1 and HMGA2. This evidence concerns the gene HMGA2 and thyroid cancer.