Regarding HSP90 capable of maintaining the conformation, stability, and function of key client proteins related to oncogenic signal transduction (i.e., mutant epidermal growth factor receptor), angiogenesis (i.e., VEGF), antiapoptosis (i.e., AKT), and metastasis (i.e., matrix metalloproteinase 2 and CD91), processes important for maintaining the cancer phenotype, it is substantially expressed at 2- to 10-fold higher levels in tumor cells compared to their normal counterparts, suggesting that it may be crucial for tumor growth and/or survival [76, 79–81]. The gene discussed is EGFR; the disease is neoplasm.