ERBB2 and cancer: HSP90, one of the most abundant molecular chaperones, is important for the maturation, stability, and activity of numerous cancer-related proteins, such as mutated p53, EarB2/Her2, Raf-1, cyclin-dependent kinases 1 and 4, Akt/PKB, Bcr-Abl, and Hif-1a, which are involved in cell signaling, proliferation, and survival, as well as neoangiogenesis, adhesion, and drug resistance [39], [40].