RAS genotyping is mandatory for the prescription of anti-EGFR (epidermal growth factor receptor) therapies in patients with metastatic colorectal cancer. The standard genotyping is assessed on formalin-fixed paraffin embedded tumour tissue. This study compares RAS and BRAF genotyping results achieved in analyzing circulating plasma DNA using OncoBEAM™ technique with those achieved using the standard genotyping techniques and formalin-fixed paraffin embedded samples.

The study will be proposed to all patients with a metastatic colorectal cancer.

Study information will be given to the patient during a routine medical examination. The patient will be included after checking inclusion criteria and signature of the informed consent form

Blood sampling (30 ml) will be performed before the initiation of the first line metastatic chemotherapy.

Inclusion Criteria:

• Adult subjects with newly diagnosed, anti EGFR treatment naïve metastatic colorectal cancer
• Standard of Care RAS/RAF tests performed on FFPE tumor sample as part of routine
• Patient information and written informed consent form signed
• Patient must be affiliated to a social security system
• Age : 18 years and older

Exclusion Criteria:

• Patient bearing non-metastatic colorectal cancer
• Patient with local relapse only
• Patient with exclusive nodal metastases
• Patient whose health contraindicates a 30 ml blood sample
• Blood transfusion within 1 week prior blood collection
• Patient having received any chemotherapy or / and radiotherapy within 15 days prior to blood collection
• History of another primary cancer within the last 5 years, with the exception of non-melanomatous skin cancer and carcinoma in situ of the cervix
• Persons deprived of liberty or under supervision