In MS, the primary clinical efficacy of S1PR modulators is achieved through their coupling with subtype S1PR1, thus regulating immune cell trafficking through sequestration of autoreactive lymphocytes in the lymph nodes and presumably reducing migration and subsequent infiltration into the central nervous system (CNS) (Roy et al., 2021; Sehr et al., 2019; Fischer et al., 2021). This evidence concerns the gene S1PR1 and myeloid sarcoma.