RET and thyroid gland papillary carcinoma: To generate in vitro models of papillary thyroid carcinoma (PTC), two cell systems were set up: primary human thyrocytes exogenously expressing the RET/PTC1 oncogene vs parental thyrocytes (model 1) [20], and TPC1 cells (PTC-derived cell line harbouring endogenous RET/PTC1) solvent-treated vs TPC1 cells treated with the TK inhibitor RPI-1 (model 2) [21].