culescu, KW Kinzler, B Vogelstein, J Willis, SD Markowitz (2008). Comparative lesion sequencing provides insights into tumor evolution. P Natl Acad Sci USA 105: 4283-4288. Page 9 of 16 EFTA_R1_01519433 EFTA02443867 209. Langer P, MA Nowak, C Hauert (2008). Spatial invasion of cooperation. J theor Biol 2