News from the cancer research community: "more than half of all human cancers have mutations that disable a protein called p53. As a critical anti-cancer watchdog, p53 masterminds several cancer-fighting operations within cells. When cells lose p53, tumors grow aggressively and often cannot be treated. ... [Researchers] have succeeded in shutting off the growth of tumors in which p53 is missing by turning up the production of TAp63 proteins, which make up one class of proteins produced by the p63 gene. TAp63 completely blocked tumor initiation, the team found, by inducing senescence, a state of growth arrest in which tumor cells are still metabolically alive but fail to divide. More importantly, turning up the levels of TAp63 in cells that did not have p53 blocked the progression of established tumors in mice. ... Tumor growth continued in the placebo group, with the tumors becoming five times larger within a week. In contrast, the tumors in the mice [producing TAp63] were abruptly shut down, and the tumors even shrank in size. Mills speculates that the tumor cells disappear because the newly senescent cells might attract the attention of the immune system, which have the ability to destroy them."