We first demonstrated significant in vivo sensitivity of two P2RY8::CRLF2/JAK2R683-mutant (DS-ALL47) and P2RY8::CRLF2/JAK2 wild-type (DS-ALL515) DS-ALL PDX models to ruxolitinib monotherapy (Fig. 6A). The gene discussed is CRLF2; the disease is acute lymphoblastic leukemia.