Figure 2
Dynamics for an untreated tumour and examples of two different sets of dynamics resulting from changed timings of a given intervention.Each graph is proportion of cells vs time, with GLY (xG) in green, VOP (xV) in solid red and DEF (xD) in blue. The dashed red lines show the proportion of VOP among aerobic cells 
. All three graphs start with same initial conditions (p(0)(=xG(0))=0.9, q(0)=0.6) and the same tumour micro-environment (ba=2.5, bv=2, c=1, n=4). In the top panel, we highlight the cyclic behaviour by noting when p and q return to their initial values given by the green circles and red hollow circles, respectively. In the second and third panel, we consider an anti-glycolytic treatment of the same strength (subtracting 3 from the fitness of GLY) and the same duration (three time steps). The difference between the second and third panel is in timing, marked in grey: the second panel starts treatment at t=0, and the third at t=10. If the proportion of a cell-type goes below 10−4 then it dies off entirely. At t=30, no cell types are extinct in the top panel; in the second and third panel, the only non-extinct cell types are GLY and DEF, respectively. This highlights the importance of the timing of therapy for evolutionary outcome.
