Population growth and control in stochastic models of cancer development

We study the joint effect of thermal bath fluctuations and an external noise tuning activity of cytotoxic cells on the triggered immune response in a growing cancerous tissue. The immune response is assumed to be primarily mediated by effector cells that develop a cytotoxic activity against the abnormal tissue. The kinetics of such a reaction is represented by an enzymatic-like Michaelis-Menten two step process. Effective free-energy surface for the process is further parameterised by the fluctuating energy barrier between the states of high and low concentration of cancerous cells. By analysing the far from equilibrium escape problem across the fluctuating potential barrier, we determine conditions of the most efficient decay kinetics of the cancer cell-population in the presence of dichotomously fluctuating concentration of cytotoxic cells. (C) 2004 Elsevier B.V. All rights reserved.