Stochastic dynamics of hematopoietic tumor stem cells.

Many tumors derive from the transformation of normal stem cells into cancer stem cells that retain their self-renewal capacity. This modern view of cancer has provided a natural explanation for the striking parallels which exist between these two different types of self-renewing cells. Here we develop a simple mathematical model to investigate the implications of this concept regarding the evolution of tumors in the hematopoietic system. Our results unequivocally demonstrate that stochastic effects related to the finite size of the active stem cell population have a profound influence on the dynamics of cancer evolution. For input parameters compatible with both the natural history of human cancer and mouse models, our results show how stochastic dynamics alone may lead to both remission in some cases and rapid expansion in others.