CSPG4 and thyroid gland carcinoma: Further studies showed that NG2 was involved in maintaining the activities of multiple RTKs, such as EGFR, FGFR, HER2, IGF-1R, VEGFR and PDGFR, suggesting that these RTKs and their downstream signaling pathways may contribute to the resistance of BRAF-mutant thyroid cancer cells to BRAF inhibitor.