Adaptive Complexity talks about a paper published this week in PNAS that lends a clue to why cancer cells can keep growing and dividing, even in an environment that lacks nutrients. Princeton's David Botstein used a model of "unnaturally" starved mutant yeast to find mutations in the TOR pathway, which is a critical stress response regulatory pathway. Follow-up studies would compare these mutations to potentially similar ones in cancer cells, which, like yeast that have been genetically modified to not be able to produce certain nutrients for themselves, will nonetheless keep growing and dividing.