TPO and differentiated thyroid carcinoma: Moreover, treatment of TPC-1 and BCPAP cells for 24 h with trametinib, a MEK inhibitor which was shown to reduce HMGA2 mRNA expression levels [11], increased TG, TPO and PAX8 mRNA levels (Figure 3b), suggesting that the MAPK pathway induces cell dedifferentiation in papillary thyroid carcinomas through HMGA2.