A previous study has shown that the COX-2 gene is able to regulate MDR1 expression in rat mesangial cells (29), and that the use of a COX-2 inhibitor, rofecoxib, was able to sensitize MTC cells to DOX in the treatment of an MTC-derived cell line in vitro (22). The gene discussed is PTGS2; the disease is medullary thyroid gland carcinoma.