B Math Biol 65: 67-93. 14. Nowak MA, F Michor, Y Iwasa (2003). The linear process of somatic evolution. P Nail Acad Sci USA 100: 14966-14969. 15. Rajagopalan H, MA Nowak, B Vogelstein, C Lengauer (2003). The significance of unstable chromosomes in colorectal cancer. Nat Rev Cancer 3: 695-701. 16. Sasaki A,