HSPA6 and cancer: Human HSP70s comprise a family of 13 members that perform their functions depending on their cellular localization, among which five members that are most concerned with cancer development are stress-inducible HSP70 (HSP72 or HSPA1) and HSPA6 (HSP70B) and constitutively expressed GRP78 (HSPA5), HSC70 (HSPA8), and mortalin (HSPA9) [11].