Abstract
In this talk, I will suggest that cancer is fundamentally a disease of the control on cell
differentiation in multicellular organisms, uncontrolled cell proliferation being a mere
consequence of blockade, or unbalance, of cell differentiations. Cancer cell populations, that
can reverse the sense of differentiations, are extremely plastic and able to adapt without
mutations their phenotypes to transiently resist drug insults, which is likely due to the
reactivation of ancient, normally silenced, genes. Stepping from mathematical models of non
genetic plasticity in cancer cell populations and questions they raise, I will propose an
evolutionary biology approach to shed light on this problem, using a description of multicellular
organisms in terms of structured cell populations both from a theoretical and partly metaphoric
viewpoint, and from a practical point of view oriented towards cancer therapeutics, as cancer is
primarily a failure of multicellularity in animals and humans. This joint approach resorts to the
emergent field of knowledge named philosophy of cancer and, more classically, to adaptive cell
population dynamics and its therapeutic control.