Ultimately, the expression of VPS33B was found to be elevated in VPS33B-overexpressing NPC cells treated with nicotine after treatment with the PI3K specific inhibitor Ly294002 via PI3K/AKT/c-Jun signaling (Fig. 5g, h) and thus the binding of c-Jun with VPS33B promoter was facilitated (Fig. 5i). This evidence concerns the gene JUN and nasopharyngeal carcinoma.