INTRODUCTION Homeostasis is a critical property of living beings that involves the ability to self-regulate in response to changes in the environment in order to maintain a certain dynamic balance aecting form and/or function. Homeostasis is of particular importance in multicellular organisms, where it is intertwined with development [2,3]. Organisms have evolved intricate control mechanisms that ensure developmental processes achieve their end points and stabilize (e.g., dierentiate) as well as allow for a degree

Disruption of Cellular Responses to the Death Signals Results in Lumen Repopulation 18 Disruption of Cellular Responses to the Mitotic Signals Results in Dysfunctional Acini 19 Disruption of Cellular Responses to the ECM Signals Results in Tumor Cell Invasion 20

Discussion 20 e Roles of TGF-β and Stroma in Homeostatic Escape in Prostate Cancer 21

Model 23 Results and Discussion 25

Conclusions 26 Acknowledgments 27 References 27

of adaptability to a range of conditions (e.g., stress or damage induced by wounding). is allows for the emergence of a more robust system that can tolerate both external and internal perturbations [4]. However, there are limitations to this tolerance, and oen it is the rare events that cause the most disruption [5]; think of the extinction of dinosaurs for an example. From an evolutionary point of view, this is a viable trade-o between the energetic cost of homeostasis versus the tness benet it would provide. In practical terms, homeostasis of living multicellular organisms is constrained in terms of the amount of disruption they can cope with and in terms of the amount of time they will remain homeostatic.