HSPA9 and hepatocellular carcinoma: Some studies have suggested that HSPA9 and HSPA4 are relevant to cellular apoptosis and promoting proliferation[41], ; HSPA9 is over-expressed in colon and hepatocellular carcinomas [43], [44], while HSPA4 is over-expressed in breast, colon, ovarian, and pancreatic cancers [45].