Microenvironmental regulation of cancer development.

Numerous studies have demonstrated that the tumor microenvironment not only responds to and supports carcinogenesis, but also actively contributes to tumor initiation, progression, and metastasis. During tumor progression all cells composing the tumor undergo phenotypic and epigenetic changes. Paracrine signaling between epithelial and stromal cells is important for the regulation of the proliferation, invasive, angiogenic, and metastatic behavior of cancer cells. Better understanding the molecular mechanisms by which stromal cells exert these effects may open up new venues for cancer therapeutic and preventative interventions.