Multicenter, inter-regional, case-control study with the primary objective of evaluating the discriminative power of the blood biomarker TFPI-1 to separate patients with histologically proven CRC from an asymptomatic control population between 50 and 75 years of age with normal colonoscopy.

Inclusion Criteria:

• Patients with suspected colorectal cancer for which colonoscopy is indicated.
• Patients between 50 and 75 years old, asymptomatic from the digestive point of view (for example referred for colonoscopy as part of a pre-operative check-up of an inguinal hernia or 3 months after an episode of complicated sigmoiditis), for whom a follow-up colonoscopy is indicated.

Note.

• If the post-inclusion colonoscopy is normal, no biopsy will be performed and patients will be assigned to the control group.
• If the colonoscopy performed after inclusion is abnormal (presence of at least one mucosal lesion), patients will be assigned to the "colorectal cancer" group or to the "polyps" group depending on the results of the anatomopathological analysis of the lesion(s)

Exclusion Criteria:

• All clinical situations outside of CRC that could increase TFPI-1 or 2 blood levels: acute coronary syndrome (unstable angina, acute myocardial infarction), severe sepsis, decompensated cirrhosis, pregnancy, chronic inflammatory bowel disease (Crohn's or ulcerative colitis), colitis or radiation rectitis.
• Endoscopic polypectomy without prior histological confirmation.
• Emergency (occlusion or peritonitis)
• Minor patients.
• Persons of full age under legal protection or unable to express their consent
• Persons not affiliated to a social security system or beneficiaries of such a system.
• Pregnant women, women in labor or nursing mothers.

Patients followed up for colonoscopy in the gastroenterology and digestive surgery departments of 5 regional hospitals in northern France