This is a prospective observational biomarker study including patients with non-metastatic, soft-tissue sarcomas (STS) for whom neoadjuvant chemotherapy is considered as the best option by the multidisciplinary sarcoma team of one of the participating centers.

Even when retrospective statistical identification for a biomarker has been achieved, the ultimate proof of its usefulness in the clinic still requires prospective evidence. Our prospective study aims to validate the prognosis value of the CINSARC signature in a prospective way. Moreover, the neoadjuvant setting is an ideal one to identify molecular predictive factors of sensitivity to chemotherapy by correlating tumor response with genetic profile of STS. Moreover, molecular profiling of treatment-refractory tumor cells may reveal alterations that are associated with drug resistance, metastatic recurrence and disease progression. The identifications of such factors in the neoadjuvant setting may help to improve the management of STS patients in the adjuvant and metastatic settings

Inclusion Criteria:

1. Histologically confirmed soft-tissue sarcoma by central review, except if the diagnosis was already confirmed by the RRePS (Réseau de Référence en Pathologie des Sarcomes et des Viscères) Network,
2. Available archived frozen tumor tissue sample or patient consenting to undergo a biopsy of the tumour for research purpose,
3. Non-metastatic disease, for which the use of chemotherapy to "downstage" the sarcoma prior to surgery, is assumed to result in better local tumor control by the multidisciplinary sarcoma team of one of the French reference centers involved in this study,
4. Age ≥ 18 years,
5. Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≤ 1,
6. Measurable disease according to RECIST v1.1 outside any previously irradiated field,
7. Neoadjuvant anthracycline-based chemotherapy proposed as the best option by the multidisciplinary sarcoma team of one of the French reference centers involved in this study,
8. No prior or concurrent malignant disease diagnosed or treated in the last 2 years except for adequately treated in situ carcinoma of the cervix, basal or squamous skin cell carcinoma, or in situ transitional bladder cell carcinoma,
9. Voluntarily signed and dated written informed consents prior to any study specific procedure,
10. Patients with a social security in compliance with the French Law relating to biomedical research (Article 1121-11 of French Public Health Code).

Exclusion Criteria:

1. Pathological diagnosis different from a soft-tissue sarcoma,
2. Histological subtypes: well-differentiated liposarcoma, alveolar soft-part sarcoma, dermatofibrosarcoma protuberans, clear-cell sarcoma, rhabdomyosarcoma,
3. Previous treatment for the sarcoma,
4. Contra-indication precluding the administration of chemotherapy as assessed by the investigator,
5. Participation to a study involving a medical or therapeutic intervention in the last 30 days,
6. Previous enrolment in the present study,
7. Pregnant or breast feeding women,
8. Patient unable to follow and comply with the study procedures because of any geographical, social or psychological reasons.