Mimetic peptides having anti-angiogenic and anti-tumorigenic properties and methods of their use for treating cancer, ocular diseases, such as age-related macular degeneration, and other-angiogenesis-dependent diseases are disclosed. More particularly, an isolated peptide comprising the amino acid sequence LRRFSTAPFAFIDINDVINF, which exhibits anti-angiogenic activity in endothelial cell proliferation, migration, adhesion, and tube formation assays, anti-migratory activity in human breast cancer cells in vitro, anti-angiogenic and anti-tumorigenic activity in vivo in breast cancer xenograft models, and age-related macular degeneration models is disclosed. The isolate peptide also exhibits anti-lymphangiogenic and directly anti-tumorigenic properties.