DOCK8 and synovial sarcoma: Patients are most often immunodepressed, with underlying acquired or inherited immunodeficiency diseases, such as hypogammaglobulinemia, common variable immunodeficiency, Wiskott-Aldrich syndrome, X-linked severe combined immunodeficiency (SCID), Dedicator of cytokinesis 8 (DOCK8) deficiency, post ablation chemotherapy, solid organ transplantation, HIV infection/AIDS, autoimmune diseases (namely SS, RA, inflammatory bowel disease, and sarcoidosis) [3,9,10,28,97,105], and less often iatrogenic immunodepression (namely, azathioprine, methotrexate or imatinib).