Figure 2.

A schematic of the model of primary seeding. The primary tumour is assumed to consist of a number of independent loci, which grow according to the logistic equation (inset) bounded by a local carrying capacity K. Each of the loci release cells into the circulation at rate λ, and out of these circulating cells a fraction p return to form new loci at the primary site. Starting with a single cell forming one locus the dynamics of the model generate an increasing number of loci, but the precise behaviour depends on the parameters of the model (see figure 4).