Several studies revealed that COX‐2 promotes tumor metastasis, for example, Zelei reported that COX‐2 is highly expressed in NPC cells, which promote the expansion of myeloid‐derived suppressor cells with a suppressive function on T cells through inducing the cytokine secretion including IL‐6 and GM‐CSF.41 Here, IL6 is linked to nasopharyngeal carcinoma.