The aim of this study is to characterize the genetic and cellular immunological parameters of metastatic digestive cancer patients having short and long responses to chemotherapy.

Inclusion Criteria:

For all patients:

• signed written informed consent

For cohort A:

• patient with metastatic colorectal cancer with first-line therapy by chemotherapy +/- surgery and with a disease-free survival > or = at 20 months
• Ct-scan realized in the previous 4 weeks and showing no progression according to the Recist criteria v1.1

For cohort B:

• patient treated for metastatic colorectal cancer and chemotherapy responder (obtention of an objective response according to the Recist criteria V1.1 in first-line therapy), with a disease-free survival < 10 months (disease progression must be confirmed by CT scan evaluation according to Recist v1.1 criteria)

For cohort C:

• patients with no metastatic rectum cancer in complete remission after chemotherapy and/or radiotherapy

For cohort D:

• patients with metastatic or locally advanced cancer in complete remission after treatment, non eligible in the other cohorts

Exclusion Criteria:

For all patients:

• patient with any medical or psychiatric condition or disease which would make the patient inappropriate for entry into this study
• patient with a neurodegenerative disease
• patient under guardianship, curator or under the protection of justice