In tumor biology research, the characterization of cellular signaling processes has largely focused on identifying the function of individual genes and proteins. Janes showed however the context-dependent nature of signaling driving cell decisions demonstrating the need for a more system based approach. The lack of attention for context dependency in preclinical research is also illustrated by the observation that preclinical testing rarely includes predictive biomarkers that, when advanced to clinical trials, will help to distinguish those patients who are likely to benefit from a drug.