Table 2 Genetic model. Boolean (logical) functions used in the genetic model depicted Figure 1. For APC, SMAD and RAS, Boolean values are set to 0, 0 and 1 respectively when genes are mutated.

APC ^t

APC ^t+1= 0 if mutated

βcat ^t

βcat ^t+1= ¬APC ^t

cmyc ^t

cmyc ^t+1= RAS ^t∧ βcat ^t∧ ¬SMAD ^t

p27^t

p27^t+1= SMAD ^t∨ ¬cmyc ^t

p21^t

p21^t+1= p53^t

Bax ^t

Bax ^t+1= p53^t

SMAD ^t

SMAD ^t+1= 0 if mutated

RAS ^t

RAS ^t+1= 1 if mutated

p53^t

p53^t+1= 0 if mutated

CycCDK ^t

CycCDK ^t+1= ¬p21^t∧ ¬p27^t

Rb ^t

Rb ^t+1= ¬CycCDK ^t