Tumor evasion from immune control: Strategies of a MISS to become a MASS

We biologically describe the phenomenon of the evasion of tumors from immune surveillance where tumor cells initially constrained to exist in a microscopic steady state (MISS) elaborate strategies to evade from the immune control and to reach a macroscopic steady state (MASS). We, then, describe "evasion" as a long term loss of equilibrium in a framework of prey-predator-like models with adiabatic varying parameters, whose changes reflect the evolutionary adaptation of the tumor in a "hostile" environment by means of the elaboration of new strategies of survival. Similarities and differences between the present work and the interesting seminal paper [Kuznetsov VA, Knott GD. Modeling tumor regrowth and immunotherapy. Math Comput Model 2001;33:1275-87] are discussed. We also propose and study a model of clonal resistance to the immune control with slowly varying adaptive mutation parameter. (c) 2005 Elsevier Ltd. All rights reserved.