Hsp90 is involved in the maturation and activation of client proteins. Often these are key proteins involved in signal transduction and regulatory pathways that in a mutated and/or deregulated form sustain an oncogenic cellular state. Consequently, the malignancy is maintained with the aid of Hsp90 upon which the mutated proteins have become particularly dependent for their activity. The requirement for the Hsp90 chaperone machine to drive the malignancy makes Hsp90 a prime anticancer target, an 'axle in a wheel' that when disrupted has been shown to be effective in killing cancerous cells. This review aims to identify potential drug targets, based on the current structural knowledge of the Hsp90-chaperone machine, that could be targeted with the aim of disrupting its functioning and promoting an anti-cancer activity.