STAG2 and thyroid cancer: As supported, our data showed that knocking down STAG2 in thyroid cancer cells clearly up-regulated p-ERK levels compared with the control, accompanied by a reduction in HER3 expression and the levels of phosphorylated HER3Tyr1197 (p-HER3Tyr1197), phosphorylated AKTSer473 (p-AKTSer473) and phosphorylated GSK3βSer9 (p-GSK3βSer9) (Fig. 6e; Supplementary Fig. 12c), and these effects could be partially reversed by MEK inhibitor GSK1120212 (Fig. 6f; Supplementary Fig. 12d).