The stress of coping with E2F loss.

E2F transcription factors are key regulators of cellular proliferation, and altered E2F activity is a common feature of tumor cells. Thus, E2F targeting is being explored as a therapeutic strategy in cancer. Importantly, recent mouse knockout studies show that concomitant loss of E2f1/E2f2 activity is associated with increased genomic instability and oncogenic potential in normal differentiating cells, a finding that might have implications for cancer therapy.