Radial percolation reveals that Cancer Stem Cells are trapped in the core of colonies

Using geometrical arguments, it is shown that Cancer Stem Cells (CSCs) must be confined inside solid tumors under natural conditions. Aided by an agent-based model and percolation theory, the probability of a CSC being positioned at border colony estimated. This estimated as function self-renewal ps; i.e., chance remains undifferentiated after mitosis. In most common situations ps low, CSCs produce differentiated cells very low rate. The results presented here show form small core in center cancer cell colony; they become quiescent due to lack space proliferate, which stabilizes their population size. result provides simple explanation for niche size, dispensing with need quorum sensing or other proposed signaling mechanisms. It also supports hypothesis metastases are likely start beginning tumor development.