FOS and graft versus host disease: In our present study, the inhibitory effects of curcumin on the development of GVHD were associated with attenuated expressions of c-Fos/c-Jun in the epithelial tissues of skin (including keratinocytes) and intestine, suggesting that decreased AP-1 signaling in skin keratinocytes and intestinal epithelial cells may at least contribute to the attenuated severity of acute GVHD in animal models.