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

Inclusion criteria

• Age ≥18 years at the time of study entry.
• Diagnosis of one of the following rare sarcoma subtype, confirmed by RRePS network:

• Clear Cell Sarcoma (CCS)
• Epithelioid Sarcoma (ES)
• Perivascular Epithelioid Cell neoplasm (PEComa)
• Desmoplastic Small Round Cell Tumours (DSRCT)
• Malignant Solitary Fibrous Tumours (mSFT)
• Alveolar Soft Part Sarcoma (ASPS)
• Epithelioid Hemangioendothelioma (EH)
• Low-Grade Fibromyxoid Sarcoma (LGFS)
• Sclerosing Epithelioid Fibrosarcoma (SEF).
• Localized/locally advanced or metastatic disease.
• In case of localized disease, treatment must not have been yet initiated before inclusion (except surgical excision).
• In case of metastatic disease, project of new line of systemic treatment must have been decided before inclusion.
• Patient followed in the center within a standard of care procedure or clinical trial.
• Archived tumor specimen at initial diagnosis available (before treatment initiation).
• Evaluable disease (measurable as per RECIST 1.1) or not.
• ECOG Performance status 0-3.
• Patient able to participate and willing to give informed consent prior to performance of any study-related procedures.
• Patient affiliated to a Social Health Insurance in France.

Exclusion criteria

• Diagnosis of all other histotypes of soft tissue sarcoma.
• Any condition contraindicated with procedures required by the protocol.
• Known history of positive test for hepatitis B virus or hepatitis C virus or human immunodeficiency virus (HIV) or known acquired immunodeficiency syndrome (AIDS).
• Any psychological, familial, geographic or social situation, according to the judgment of investigator, potentially preventing the provision of informed consent or compliance to study procedure.
• Pregnant or breast-feeding woman.
• Patient who has forfeited his/her freedom by administrative or legal award or who is under guardianship.