The level of CHOP, ATF-4, and XBP-1 protein was significantly upregulated, suggesting that the activation of ER stress pathway may have a significant role in the anti-tumor effect of B63.191 Lin et al.192 revealed that Tetrandrine (TET) treatment of NPC cells increased apoptosis, upregulated the expression level of calpain 1, calpain 2, caspase 12, IRE-1α, IRE-1 β, GADD153, Glucose-regulated protein 78 (GRP78), ATF-6α, and ATF-6, indicating that TET induced cell apoptosis through ER stress. This evidence concerns the gene ATF6 and nasopharyngeal carcinoma.