Cancer Clones Revised

Abstract Cancers are hard to treat, and this is largely because cancer cells evolve and diversify through space and time, in patients. The study of clonal evolution relies on the study of cancer cell lineages, and the cutting of these lineages into clones, each clone representing cancer cells with distinctive properties relevant to cancer development and treatment. This notion of clone implies a (set of) simplification(s) that misrepresents the reality. The simplification has been useful and productive, but I argue that maintaining a critical awareness of what is done through this simplification can also be useful and productive. I distinguish three types of simplifications and show that each can offer a panel of therapeutic alternatives that may complement our arsenal of strategies in the battle against clones. The clinical challenge of better treating cancer partly relies on better defining (delineating) clones, but also partly on the more fundamental way we conceive clones. With or without changing the definition, changes in the way we conceive of clones induce changes in the way we treat clones.