Inclusion Criteria:  I1. Adult (≥18 years old), male or female I2. Patient with a histologically or cytologically-confirmed diagnosis of unresectable or metastatic GIST harboring the D842V mutation in the PDGFRα gene I3. Patient treated with Avapritinib I4. Non opposition to the use of her/his data  Exclusion criteria :  E1. Patient not meeting all the inclusion criteria