Switching TGF beta from a tumor suppressor to a tumor promoter

TGF beta acts as a potent tumor suppressor and tumor promoter in a context dependent manner. Tumor suppressive functions include inhibition of cell proliferation, induction of apoptosis and regulation of autophagy. As tumors develop they switch their response to TGF beta and utilise this factor as a potent promoter of cell motility, invasion, metastasis and tumor stem cell maintenance. These multifactorial tumor influencing actions of TGF beta involve regulation of an increasing number of signal transduction pathways employing a diverse range of signaling molecules. Understanding the molecular mechanisms of how tumor cells respond to TGF beta and switch their response to this cytokine during disease progression is vital for both the development and the informed use of potentially powerful TGF beta targeted therapeutics.