HSPA1A and cancer: HSPA2 shares 86.3% amino-acid sequence homology with HSPA8 (HSC70), a constitutively expressed housekeeping chaperone; 83.5% with HSPA1 (aliases: HSP70-1, HSP70i, HSP72, HSP70.1), a stress-inducible protein which is frequently overexpressed in cancer cells; and 78.3% with HSPA6 (HSP70B’), a strictly stress-inducible, short-lived chaperone that is absent in cells under physiological conditions [7].