is the labeled form of Suberoylanilide Hydroxamic Acid (S688700), which is a potent, selective, cell permeable histone deacetylase inhibitor (HDAC), displays anti-angiogenic activity by interfering with VEGF signaling in human umbilical vein endothelial cells (HUVECs) and induces differentiation in human breast cancer cells. Also it is a potent histone deacetylase inhibitor.