Inclusion Criteria:  Major patient with or suspected of myelodysplastic syndrome (WHO definition) at diagnosis and/or during follow-up, which is managed at the level of the Cancer-Hematology Institute of the Brest CHRU Presence of biological material collected within the CRB Patient's consent obtained  Exclusion Criteria :  Minor and pregnant woman Lack of biological material collected within the CRB Refusal to participate: lack of consent - Unable to consent Patient under judicial protection: guardianship, curatorship ...