Cancer: an evolutionary perspective

Abstract

Cancer is intricately linked to our evolutionary history. The origin and progression of cancer can hence be better understood when viewed from an evolutionary perspective. In this review, we portray the fundamental fact that within the complex ecosystem of the human body, the cancerous cells also evolve. Just like any organism, they face diverse selective pressure to adapt to the tumor environment. There exists a competitive struggle that eliminates the unfit, leaving the well-adapted to thrive. Sequential acquisition of “driver mutations”, chromosomal instability triggering macromutations and punctuated bursts of genetic changes can all hypothetically contribute to the origin and evolution of cancer. We further describe that like in any ecosystem, cancer evolution involves not just the cancerous cells but also its interaction with the environment. However, as cancer evolves, individual cells behave more like a unicellular organism focused on its own survival. We also discuss evidences where cancer has evolved through transmission between individuals. An evolutionary analogy can open up new vistas in the treatment of this dreadful disease