This study investigates ways to better diagnose certain types of cancer, such as Rhabdomyosarcoma (RMS) and Nonrhabdomyosarcoma soft tissue sarcoma (NRSTS). Rhabdomyosarcoma is a cancer that forms in soft tissue, like muscles, while NRSTS refers to a group of rare cancers that also form in soft tissues. The purpose of the study is to improve diagnostic methods for these conditions.

Participants in the study will undergo various procedures to help researchers understand more about these cancers. These procedures are part of the study's efforts to gather detailed information about the different types of soft tissue sarcomas.

• Who can participate: Adults with a diagnosis of Rhabdomyosarcoma (RMS), Nonrhabdomyosarcoma soft tissue sarcoma (NRSTS), or Unclassified soft tissue sarcoma are eligible.
• Study details: Participants will take part in procedures designed to gather information about their specific type of cancer. These procedures are essential for the study's goals and will not involve any medication.