ERBB2 and neoplasm: The involvement of the HSP90 (heat shock protein 90) system in the cellular stabilization of oncogenic protein kinases such as ErbB2, BRaf-V600E, FGFR-G719S, BCR-ABL, and EML4-ALK has marked it as a prime target for drug discovery, and a number of potent HSP90 inhibitors are at various stages of clinical trial in a range of tumor types (Neckers and Workman, 2012).