In this study, we observed that although STAG2 was down-regulated in thyroid cancers and knocking down STAG2 in BRAF-mutant thyroid cancer cells caused a conspicuous up-regulation of phosphorylated ERK (p-ERK), it virtually had no effect on malignant phenotypes of these cells and their response to MEK inhibitor. This evidence concerns the gene STAG2 and thyroid gland carcinoma.