Among HSP70 family, five members have been especially well examined in association with cancer, which are stress-inducible HSP70s, HSP72 (HSPA1) and HSP70B (HSPA6), and constitutively expressed HSP70s, HSC70 (HSPA8), GRP75/Mortalin (HSPA9), and GRP78 (HSPA5) [51,52]. Here, HSPA6 is linked to cancer.