PDCD4 (Programmed cell death 4) encodes a tumor suppressor protein whose expression is lost in progressed carcinomas of lung, breast, colon, and prostate. The expression of PDCD4 gene is strongly induced during apoptosis in a number of cell types. It is modulated by cytokines in natural killer and T cells. Recombinant human PDCD4, was expressed in E.coli and purified by conventional chromatography techniques.