Why Cancer Rates Increase with Age

A new article by Rozhok and DeGregori uses an evolutionary lens to propose a more sophisticated analysis of why cancer becomes more common with age, and the role of tissue ecology.

Rozhok, A., & DeGregori, J. (2019). A generalized theory of age-dependent carcinogenesis. ELife, 8. https://doi.org/10.7554/eLife.39950

Abstract: The Multi-Stage Model of Carcinogenesis (MMC), developed in the 1950 s-70s, postulated carcinogenesis as a Darwinian somatic selection process. The cellular organization of tissues was then poorly understood, with almost nothing known about cancer drivers and stem cells. The MMC paradigm was later confirmed, and cancer incidence was explained as a function of mutation occurrence. However, the MMC has never been tested for its ability to account for the discrepancies in the number of driver mutations and the organization of the stem cell compartments underlying different cancers that still demonstrate nearly universal age-dependent incidence patterns. Here we demonstrate by Monte Carlo modeling the impact of key somatic evolutionary parameters on the MMC performance, revealing that two additional major mechanisms, aging-dependent somatic selection and life history-dependent evolution of species-specific tumor suppressor mechanisms, need to be incorporated into the MMC to make it capable of generalizing cancer incidence across tissues and species.