Validation of in Vitro Method for Anti-MCPyV Immunotherapy on Patients With Cutaneous Merkel Cell Carcinoma

Inclusion Criteria: * Patients \>= 18 years old; * Diagnosed with Merkel cell carcinoma of skin, ongoing for local treatment, systemic treatment, complementary treatment or an active follow-up; * Informed for the study and no-opposed for participation; * Affiliated with a social security scheme or in an equivalent situation. Exclusion Criteria: * Patients ongoing another interventional clinical trial; * Patients under guardianship or trusteeship; * Pregnancy or breastfeed; * Patients refusal.