Multimodal Immune Characterization of RAre Soft Tissue Sarcoma - MIRAS Project From SARRA (SARcome RAre) Project of the French Sarcoma Group

This study looks at how the immune system interacts with rare types of soft tissue cancer (called sarcoma) in adults. Researchers want to collect tumor samples and blood to understand why these cancers behave the way they do, which could lead to better treatments. **You may be eligible if...** - You are 18 or older - You have been diagnosed with one of nine specific rare sarcoma types (such as Clear Cell Sarcoma, Epithelioid Sarcoma, or Alveolar Soft Part Sarcoma) - Your disease is localized, locally advanced, or has spread to other parts of the body - You have stored tumor tissue from your original diagnosis - You are being seen at a participating center **You may NOT be eligible if...** - You are under 18 - You have already started treatment for localized disease (other than surgery) - Your performance level (ability to carry out daily activities) is very poor (ECOG 4) Talk to your doctor to see if this trial is right for you.