Evolutionary Oncology: Non Genetic Mechanisms of Ancestral Origin Involved in Cancer Drug Resistance

From the perspective of evolutionary oncology, cancer represents a unicellularized cell system consisting of a self-renewing, oxygen-sensitive stemgermline and an oxygen-resistant somatic tumor bulk cell population generated through germ-to-soma transition processes and somatic proliferation. In this configuration, cancer shows limited analogy to the multicellular organization of its host but displays deep evolutionary homology with the unicellular systems of parasitic amoebae, reflecting its origin in the common ancestor of Amoebozoans and Metazoans. The hypoxic stemgermline is the central driver of cancer’s cell system. Because its genome is highly vulnerable to hyperoxia, it requires continuous protection and, when necessary, replacement through reconstituted sublines. The non-genetic mechanisms underlying cancer drug resistance are interpreted here as ancestral survival programs that originated in the common ancestor approximately one billion years ago during two major evolutionary oxygen transitions. These programs are reactivated in the unicellularized cancer system to protect genome integrity under environmental and therapeutic stress. Over evolutionary time, these survival mechanisms evolved into highly robust and resilient networks, which may explain the remarkable persistence of the parasitic cancer cell system despite therapeutic intervention. Survival is maintained through coordinated programs of genome reconstruction and cycles of cellular plasticity that are activated when either the stemgermline or the somatic tumor population is exposed to intra-tumoral stressors or anticancer therapies. By placing cancer drug resistance within this deep evolutionary framework, evolutionary oncology offers a new conceptual basis for understanding cancer resilience and may guide the development of future therapeutic strategies aimed at targeting these ancient survival programs.