The early growth of cancer.

In this paper, we compare two types of stochastic models for the initial growth of cancerous tumors. In one type, the random element enters via the initial time of growth or via the initial size of the growth clone. In the other type, tumors differ from one another essentially via their growth rates. We present a simple test to distinguish between the two types when tumor size distributions are available from several time points. Size distributions are the key elements of such kinetic analysis given the limitation that an individual tumor can be measured only once, at the time of sacrifice of an experimental animal. We discuss these concepts in connection with data from particular experiments on carcinogenic growth in the livers of mice.