The seminal publication of evolutionary biologists John Maynard Smith and Eörs Szathmáry in 1995 advanced the theory of major evolutionary transitions in the process of evolution of biological entities on Earth. They argued that these transitions went for millions of years through several major changes in the way genetic information was organized and transmitted from one generation to the next. Also, in their theory it was suggested that cancer is a disease that emerged out of the transition from single-celled organisms to multicellular organisms (animals, plants, fungi), half a billion years ago. Ever since then, evolution at the organismal level has been developing defenses to keep in check the potential for evolution at the cellular level.
Cancer cells can be considered as microcosms of evolution. When tumors develop there is a mosaic of mutant cells competing for space and resources, while trying to evade predation by the immune system and can even cooperate to disperse and colonize new organs. The evolution of neoplastic cells explains both why we get cancer and why it has been so difficult to cure cancer tumors.
Professor Mel Greaves advanced in 2000 his evolutionary ideas on cancer with the book: Cancer: and Evolutionary Legacy” In which he proposed that “….Cancer is an evolutionary problem. First, and foremost, the process of progression from neoplastic to malignant tissue is a process of natural selection by which mutant clones evolve to escape cell cycle checkpoints, apoptosis, and other host defenses. This is the basis for the emergence of resistance and relapse after treatment. Second, cancer is a disease that emerged out of the transition from single-celled organisms to multicellular organisms, half a billion years ago. Third, and most difficult to assess, evolution has spent most of human history tuning our bodies for a set of experiences that most of us, happily, no longer share. Our modern lifestyles may relieve us from some of that suffering while also imposing new hazards for which our bodies are singularly unprepared. This review examines a series of recent research papers on the subject of evolution and cancer development. Explaining the basic theories based on scientific research, cancer can be placed within the broad framework of evolution. Cancer makes more sense in the light of evolution, and most cancer investigators would agree that taking into account the evolutionary dimension can promote more effective therapeutic trends.
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