PECAM1 and leukemia: Transplantation of AML BM MNCs resulted in a lesser degree of leukemia-induced BM vascular changes in Spred1ECΔ/Δ recipients compared with wt recipients (Fig. 4g, right panel; Additional file 1: Fig. S10m, right panel), suggesting that constitutively higher expression of miR-126, as occurred in ECs from Spred1ECΔ/Δ mice, may rescue in vivo TNFα-induced miR-126 depletion and loss of CD31+Sca-1high ECs.