Synovial sarcoma (SS) is the most common soft-tissue cancer among young adults. It is an aggressive tumor type in great need of new treatment options. SS tumors are defined by a specific genetic change that causes two separate genes to fuse into one. This new fusion-gene produces the SS18-SSX protein which is thought to remodel the cells epigenome, resulting in the activation and inactivation of a large number of genes. As SS18-SSX cannot be inhibited by any known drugs, we aim to identify the genes and regulatory elements that are directly affected by the protein. We have developed a novel SS mouse model and collected a large series of human tumors in order to study the effects of SS18-SSX in the context most relevant to patient. We will then use state-of-the art approaches to identify and disrupt the most important changes caused by SS18-SSX with the goal of identifying new treatment options for patients with this deadly disease.