Programmed Cell Death Protein 4 (PDCD4) is a member of the PDCD4 family. PDCD4 and EIF4A1 form a heterotrimer. One molecule of PDCD4 binds two molecules of EIF4A1. PDCD4 takes part in apoptosis via inhibiting translation initiation and cap-dependent translation.PDCD4 promotes colonic neoplastic transformation and tumor invasion. PDCD4 is an important target for microrna R-21 in breast cancer cells. Shortage of PDCD4 expression is associated with colorectal cancer. Overexpression of PDCD4 in carcinoid cells results in inhibition of cell proliferation.