Figure 1. On-target and off-target based drug repurposing.

A. Cartoon illustrating the repurposing of drugs (A; B) for different cancers based on their intended targets A and B playing a functional role in cancer. The initial indication may be another cancer or a cancer-unrelated disease. B. Cartoon illustrating the repurposing of a multi-targeted drug (C) for a specific type of cancer based on inhibition of an off-target (G) that plays a functional role in that cancer. The initial indication may be another cancer or a cancer-unrelated disease.