HSPA5 and cancer: The use of metformin increased the expression of several factors, including the heat shock 70-kDa protein 5 (Hspa5), also known as binding immunoglobulin protein (BIP), C/EBP homologous protein (CHOP), and caspase-12, which activate endoplasmic reticulum (ER) stress conditions, leading to cancer cell apoptosis [55,64].