PTGS2 and thyroid cancer: Then, we examined the expression of TFAP2B/COX-2 at the protein level in human thyroid normal cell lines (Nthy-ori-3-1), and thyroid cancer cell lines (TPC-1, KTC-1, BCPAP, K2) by western blotting (Fig. 2a), the amount of transcripts of TFAP2B and COX-2 in each cell is shown in Supplementary Fig. B.