Drug target identification through systems biology

• Computer modelling can guide drug target validation studies.
• Essential targets can be further ranked based on their quantitative impact.
• Quantitative network differences can provide selectivity to non-unique targets.

To rationalise drug target selection, we should understand the role of putative targets in biological pathways quantitatively. We review here how experimental and computational network-based approaches can aid more rational drug target selection and illustrate this with results obtained for microbes and for cancer. Comparison of the drug response of biochemical networks in target cells and (healthy) host cells can reveal network-selective targets.