When investigating the effects of therapeutic interventions on the probabilities of cancer initiation, we found that a lower rate at which self-renewal is acquired (gamma), a lower expansion factor due to PDGF-overexpression (C), and a higher death rate of mutated SR cells (d) decrease the risk of PDGF-driven glioma initiation, while in the case of NF1-driven gliomas, changes in SR cell characteristics (such as the fitness advantage conferred by loss of tumor suppressors) in addition to a potential gamma effect associated with NF1 loss can modify the chance of cancer initiation. This evidence concerns the gene NF1 and glioma.