For these studies, we selected three Ph-like B-ALL PDX models, two CRLF2-re (P2RY8-CRLF2/JAK2 T875N, P2RY8-CRLF2/JAK2 R683S), and one with ATF7IP-JAK2 fusion. The gene discussed is JAK2; the disease is acute lymphoblastic leukemia.