This is a new project that anticipates the need to delineate combinations of differentiating inducing agents that may have utility in the clinic in the treatment of malignancies. Previous findings in the laboratory indicated that combinations of butyric acid and RA synergistically induce the differentiation of HL60 cells. This project seeks both an understanding of the mechanisms for this synergy and a determination of other tumor types that may respond to differentiation therapy. Agents to be studied are not limited to RA and butyric acid.