Steroid　receptor　coactivator-3　(SRC-3),　also　known　as　AIB1,　is　a　member　of　the　p160　steroid　receptor　coactivator　family.　Since　SRC-3　was　found　to　be　amplified　in　breast　cancer　in　1997,　the　role　of　SRC-3　in　cancer　has　been　broadly　investigated.　SRC-3　initially　was　identified　as　a　transcriptional　coactivator　for　nuclear　receptors　such　as　the　estrogen　receptor　(ER),　involved　in　the　proliferation　of　hormone-dependent　cancers.　However,　increasing　clinical　evidence　shows　that　dysregulation　of　SRC-3　expression　in　several　human　hormone-independent　cancers　is　correlated　with　pathological　factors　and　clinical　prognosis.　Recently,　both　in　vivo　and　in　vitro　studies　demonstrate　that　SRC-3　may　influence　a　number　of　cancer　cellular　processes　in　several　ways　independent　of　nuclear　receptor　signaling.　In　addition,　an　SRC-3　transgenic　mice　model　shows　that　SRC-3　induces　tumors　in　several　mouse　tissues.　These　results　indicate　that　the　role　of　SRC-3　in　cancer　is　not　just　as　a　nuclear　receptor　coactivator.　The　focus　of　this　review　is　to　examine　possible　SRC-3　roles　in　cancer,　other　than　as　a　nuclear　receptor　coactivator.