Ampelopsin (64) is one of the most important flavonoids found in Ampelopsis grossedentata. The expression of ER stress-dependent proteins, like HSPA5, p-ElF2A, spliced ATF6, DDIT3 and EIF2AK3 increases in breast cancer MCF-7 cells and MDA-MB-231, after treatment with ampelopsin (64). This evidence concerns the gene HSPA5 and breast carcinoma.