Recipient E-selectin is required for efficient engraftment of BCR-ABL1⁺stem cells. (A-B) Kaplan-Meier curves for (A) mortality due to CML-like leukemia and (B) overall survival of B6129 F2 control (solid line, n = 33) or E-selectin KO (dotted line, n = 15) recipients of BCR-ABL1–transduced BM from WT B6129F2 donors, administered via an i.v. route. The difference in overall survival between the 2 cohorts was significant (P = .021, Mantel-Cox test). (C) Engraftment of E-selectin mutant recipients, assessed by Southern blotting of leukemic cell DNA as in Figure 2B. Note that E-selectin KO i.v. leukemia samples in lanes 7, 10, and 13 had proviral copy number ≥2, indicating engraftment by leukemia-initiating cells with multiple proviral integrations per cell. (D) Intrafemoral transplantation increases engraftment of E-selectin mutant recipients. Kaplan-Meier survival curve for B6129 F2 control (solid line, n = 8) or E-selectin KO (dotted line, n = 13) recipients of BCR-ABL1–transduced BM from WT B6129 F2 donors, administered by direct i.f. injection. All mice that succumbed within 2 months of transplantation developed CML-like leukemia. There was no significant difference in overall survival between the 2 groups (P = .62, Mantel-Cox test).