Networks of tumor suppressors

The concept of tumor suppressor networks comes as a logical consequence of the increasing understanding of the biology of tumor suppressor genes and oncogenes. Indeed, it has been gratifying to realize during the past decade that the products of tumor suppressor genes and oncogenes are often involved in the kind of guardian–delinquent relationship, or cat-and-mouse game suggested by the genetic evidence. Thus, some oncogenes directly cancel the protective activities of tumor suppressors and, reciprocally, there are some tumor suppressors that detect the presence of oncogenes and counteract their effects. Our understanding of the signaling network built by these gene products is still sketchy but rapidly growing (Figure 1), and this was the focus of the workshop ‘Tumor Suppressor Networks’.