TUMORIGENESIS AND CELL EVOLUTION

All kinds of hypotheses have been proposed to explain the mechanism of tumorigenesis. Up until now, we have not had any generally acknowledg ed model that helps us understand the process. In this paper, I propos e a dynamic model of how tumor cells escape the supervision of the imm une system; I also examine the possibility that tumorigenesis is a two -stage process. Finally, I suggest that our understanding of the molec ular level of tumorigenesis be reappraised.