STAT3 and chordoma: As revealed in Fig. 4A, B, overexpression of CMTM3 decreased EGFR expression level, p-EGFR and p-STAT3, but no significant differences were observed in p-AKT or p-ERK1/2 in chordoma cells as analyzed in Fig. 4E, F. Moreover, knockdown of CMTM3 increased EGFR expression level, p-EGFR and p-STAT3 as shown in Fig. 4C, D, and analyzed in Fig. 4G, H. To further confirm the above results, we used IHC staining to analyze EGFR expression level.