In the last decades, cancer treatment was based on surgery, radiotherapy and chemotherapy.

Recently, treatments have largely evolved, first with targeted therapies (notably tyrosin kinase inhibitors, TKI) and then with immune checkpoint inhibitors (ICPI, notably anti-CTLA-4 and anti- PD1). The last ones can induce durable anti-tumoral responses in patients, even if metastases are present. Their mechanisms of action are focused on the activation of immune system in order to eliminate the tumor. ICPI, because of their mechanisms of action, target immune tolerance key components and can induce important immune toxicities (colitis, hepatitis, dermatitis, thyroiditis ...), leading to early discontinuation of treatment, severe or chronic morbidity, and can sometimes be lethal. It is of importance to detect patient at risk of irAEs, because of the increasing use of ICPI and the long- term response capacity in treated patients.

Inclusion Criteria:

• patient with cancer, whatever initial tumoral histology and disease stage under ICPI treatment (anti-PD1 and/or anti-CTLA-4)
• age > 18
• followed in oncology, pneumology, dermatology, gastroenterology departments of Amiens-Picardie University Hospital or Saint Quentin hospital
• who received verbal and written information, and signed the consent form for the study

Exclusion Criteria:

• non ICPI treated patients
• patient who received a first line of ICPI treatment
• patient who received or is receiving MEK inhibitors as a treatment (because of possible lower response to ICPI treatment when associated)