Frank, S. A. 2013. Microbial biology: regulatory design prevents cancer-like overgrowths. Current Biology 23:R343-R346.

Cancer occurs when a subpopulation of cells grows faster than normal. Such overgrowth can reduce the efficiency and survival of the overall cellular population that makes up the individual. In microbes, a mutant that consumes resources faster and less efficiently may grow faster [1]. Fast, inefficient growth allows a mutant to outcompete its neighbors and spread, reducing the overall efficiency of the local population of cells. In this regard, rapidly growing and inefficient microbial mutants resemble cancer. However, simply equating overly rapid growth in microbes to cancer is, by itself, not very interesting. The interesting aspect arises when we consider the possible consequences for the design of regulatory control systems in microbes. In mammals, cells and tissues are protected against uncontrolled growth by numerous regulatory systems that monitor mutations and provide checks and balances on cell cycle progression, such as the p53 network [2]. I previously suggested that microbial regulatory control might also be designed to protect against the emergence of rogue lineages, so that mutations that enhance growth and lower efficiency become less likely to spread [3]. However, there was no clear evidence for such controls, perhaps because it is not usual to interpret microbial biology in terms of age-related diseases such as cancer. A new study by Diard et al. [4] now shows how regulatory design in a bacterium controls rapidly growing mutant lineages.