The Eco-Evolutionary Ground State Theory of Cancer and Why Cancer Develops

Why cancer develops remains one of the central unsolved problems of biology. The Eco-Evolutionary Ground-State Theory of Cancer proposes that malignant transformation results from the conditional reactivation of an ancient ecological survival system whose evolutionary origins extend deep into early eukaryotic evolution. The theory reconstructs approximately one billion years of cancer genome evolution. It proposes that the common ancestor of Amoebozoa, Metazoa, and Fungi (AMF) evolved adaptive regulatory programs enabling survival under fluctuating ecological conditions, particularly changing oxygen availability. Rather than disappearing during the evolution of multicellularity, these programs became integrated into the metazoan genome as an evolutionarily conserved ancestral genomic compartment that normally remains epigenetically suppressed. Malignant transformation is initiated when an irreversibly damaged self-renewing host cell escapes apoptosis, enters reparative senescence, and undergoes unicellularization through reactivation of this ancestral genomic compartment. This transition establishes the eco-evolutionary stemgermline, which functions as the primary regulatory system governing carcinogenesis, tumor progression, cellular plasticity, genome reconstruction, metastatic dissemination, and therapeutic resistance. The genomic instability and phenotypic heterogeneity of malignant tumors are interpreted as downstream consequences of this hierarchical organization rather than its primary cause. The theory further proposes that recurrent unicellularization originally evolved as an adaptive mechanism during the transition to multicellularity but subsequently became transformed through host co-evolution into a parasite-like cellular system. By integrating genome evolution, stemgermline biology, oxygen ecology, and host–parasite co-evolution, the Eco-Evolutionary Ground-State Theory provides a unified evolutionary explanation for both the origin of cancer and the remarkable biological properties that characterize malignant disease.