TGF-β antagonists: Why suppress a tumor suppressor?

Tumor metastasis is the major determinant of cancer patient survival.This ultimate phase in tumorigenesis depends on the ability of a tumor cell to invade the stroma, migrate in and out of blood or lymphatic vessels, and survive and re-establish itself at a secondary site.A large number of papers have provided strong evidence for a role of TGF-β in tumor invasion and/or metastasis (1-6).Now, two papers in this issue of the JCI highlight this clinically significant action of TGF-β in tumorigenesis and provide very encouraging results regarding both the efficacy and the low toxicity of a soluble TGF-β receptor antagonist that effectively reduces tumor spread (7, 8).