Additional Study Information: The purpose of this study is to find out if an investigational drug, called ADP-A2M4, is safe and how well it works in attacking Synovial Sarcoma or Myxoid/Round Cell Liposarcoma (MRCLS) cancer cells. The study involves taking certain types of immune cells from the blood, called T cells, and changing them in a laboratory before putting them back into the bloodstream, with the aim of helping them to attack and kill cancer cells. It is hoped to learn if these genetically changed T cells are safe and work to kill these cancer cell types.