Metadherin, also known as protein LYRIC or astrocyte elevated gene-1 protein (AEG-1) is a protein that in humans is encoded by the MTDH gene. MTDH (AEG-1) is involved in HIF-1alpha mediated angiogenesis. MTDH also interacts with SND1 and involved in RNA-induced silencing complex (RISC) and plays very important role in RISC and miRNA functions. MTDH has been shown to interact with spliceosome proteins in the cell nucleus and regulate the process of alternative splicing. MTDH induces an oncogene called Late SV40 factor (LSF/TFCP2) which is involved in thymidylate synthase (TS) induction and DNA biosynthesis synthesis. Late SV40 factor (LSF/TFCP2) enhances angiogenesis by transcriptionally up-regulating matrix metalloproteinase-9 (MMP9). MTDH acts as an oncogene in melanoma, malignant glioma, breast cancer and hepatocellular carcinoma. It is highly expressed in these cancers and helps in progression and development of these cancers. It is induced by c-Myc oncogene and plays very important role in anchorage independent growth of cancer cells. Elevated expression of the metastasis gene metadherin (MTDH), which is overexpressed in more than 40% of breast cancers, is associated with poor clinical outcomes.