Respect Thy Neighbor!

Abstract
The tissue microenvironment surrounding tumor cells may not be just a passive bystander during tumorigenesis. In their Perspective, Radisky and Bissell discuss new work showing that mice with stromal cells unable to respond to the cytokine TGF-rapidly develop epithelial tumors ( Bhowmick et al.). The Perspective authors explore the implications of the finding that stromal cells are a protective influence on epithelial cells, preventing them from becoming tumorigenic.