Drug repurposing: a retrospective revolution in breast cancer medicine

Abstract Breast cancer is a complex disease involving numerous pathways, making effective treatment quite challenging. Among the current scenario, drug repurposing serves as one of the best alternatives for drug discovery as a time-efficient and cost-effective strategy to determine new therapeutic indications for previously approved drug molecules. This is the reason behind the increased popularity of drug repurposing not only in the pharma industry but also in the civil sector and academics as a faster and less expensive way to increase the repertoire of licensed cancer therapies. In the current review, we have tried to perform an in-depth review of the current state of repurposed medications available for the treatment of breast cancer. Studies conducted on various noncancer medications showing possible anticancer effects were also included. Furthermore, the various repurposed drugs available for breast cancer treatment have been further segregated according to their indicative class and possible mechanism of action.