To this end, ER stress-stimulated melanoma cells were pre-treated with IRE1α specific inhibitor STF-083010 or MKC8866, and the increased PD-L1 expression induced by TG or HA15 was significantly suppressed by the inhibition of IRE1α in either transcriptional level or protein level (Additional file 1: Fig. S12E-F). The gene discussed is ERN1; the disease is melanoma.