Colorectal cancer is the third most common cancer worldwide and its progression-free survival is still low, around 10 months. Thirthy to 50% of patients do not respond to chemotherapy upon initiation of treatment, suggesting that early development of chemoresistance mechanisms remains a major challenge. In order to better characterize these mechanisms, the aim is to develop a model of tumoroids derived from patients with a colorectal tumors prior to any systemic anti cancer treatment. This project will both allow us to study the role of the immunological microenvironment in chemoresistance and identify new predictive markers of tumor response. It will then serve to develop innovative personalized medicine strategies by targeting the newly identified mechanisms. This study should in fine help to improve the cancer patient's care.

Inclusion Criteria:

• Male and female over 18 years old.
• Managed at the CHUGA for a colorectal adenocarcinoma
• With an indication for immediate surgical resection as part of the care.
• Patient naive from neo-adjuvant chemotherapy
• Patient did not object to the CRC-ORGA-2 study

Exclusion Criteria:

• Patients protected by law (pregnant or breastfeeding women, minors, patients under guardianship or trusteeship, persons deprived of their liberty or hospitalized under duress).
• Patients with positive HIV, HBV, HCV serology.

colorectal adenocarcinoma, naive from neo-adjuvant chemotherapy, indication of surgical resection