The levels of TNF-α, an M1 phenotype cytokine secreted by macrophages, were decreased after co-cultured with ZIC2-overexpressing NPC cells, but the secretion of TGF-β, M2 phenotype cytokines and the expression of M2-related surface marker ARG-1 were increased (Fig. 2F). This evidence concerns the gene ARG1 and nasopharyngeal carcinoma.