TP53 and cancer: When comparing the relative importance of the three populations (SR, TA, and SRTA cells) for cancer initiation, we found that the probability of cancer initiation from SRTA cells dominates the dynamics in the PDGF-induced case for almost all parameter choices (Figs. 3 and S3), while in the NF1-driven case, only SR cells can lead to cancer initiation (Fig. S4) if there is no appreciable gamma effect associated with either NF1 or TP53 loss.