The power behind the throne; senescence and the hallmarks of cancer

Abstract

The hallmarks of cancer was an attempt to describe the underlying principles of carcinogenesis. In their latest iteration, there is a particular focus on the role that the microenvironment and signalling between cancer cells and their neighbors play in the pathology of tumors. Since the original description of the hallmarks there has been a huge leap forward in our understanding of the biology of cellular senescence promoting it from an autonomous tumor suppressor to a complex, dynamic phenotype that can sometimes be tumor suppressive, but sometimes oncogenic. In particular, our understanding of the diverse non-autonomous effects that senescent cells can have upon both cancer cells and the tumor microenvironment suggests that senescent cells could play a major role in many human cancer types. Here we suggest that cellular senescence could underpin the biology of many of the hallmarks of cancer, making it the true power behind the throne.