Cancers are composed of heterogeneous cell populations that arise from a single cell of origin and diversify through the accumulation of somatic mutations, making them subject to
Darwinian evolution. This
clonal evolution leads to
intratumor heterogeneity, in which distinct subclones coexist within the same tumor, as demonstrated by multiregion sequencing studies revealing branched evolutionary patterns where the majority of mutations are not shared across all tumor regions. However, the success of these mutant clones depends not only on their genetic traits but also on their ability to disrupt tissue
homeostasis, meaning that an evolutionary view of cancer must be complemented by an ecological perspective to understand how cancer cells invade and remodel their microenvironment. Beyond competition,
game theory has been applied to model cooperative interactions between tumor cell subpopulations, showing that clones can collectively acquire the hallmarks of cancer through mutualistic relationships. Ecological frameworks treat tumors as ecosystems in which cancer progression reflects a disruption of the balance between interacting cellular populations and the
tumor microenvironment. These ecological and evolutionary dynamics can be exploited therapeutically, as the population-level vulnerabilities of tumors offer new strategies to drive cancer subpopulations to extinction. ==Statistical methods==