A Multistage Model for Tumor Progression

Abstract

Because cancer is among the leading causes of death in the United States and most developed societies, it is of great medical and scientific interest. In the clinic, one deals with screening, diagnosis, and treatment; however, the individual who has not developed the disease is most interested in risk reduction. In either case, knowledge about the ways that cancer can develop is important. Just as the research literature concerning cancer is immense, so too are there many different kinds of mathematical models of cancer. Among those of interest are models of cell cycle kinetics (Kimmel and Axelrod, 1991 ; Novak and Tyson, 1993), carcinogenicity (Ioannides et al., 1993), models based on tumor growth (Mehl, 1991), multistage models of tumor development (Moolgavkar and Knudson, 1981; Stein and Stein, 1990; Moolgavkar and Luebeck, 1992), and metastasis (spreading of a cancer from its site of origin; Tracqui, 1995), and models of treatment outcomes (Retsky et al., 1994; Duchting et al., 1996). Growth models have already been discussed. Here let us consider a multistage model of tumor development, because most tumors require mutations in three or more genes involved in growth control (cellular protooncogenes). The model used here is based on colon cancer, for this cancer affects men and women alike, and is known to be influenced by dietary and lifestyle-related factors.

The universe is not actually malignant, it only seems so.