FOXF1 and cancer: Since homozygous deletion of Foxf1 in mouse endothelial cells (Pdgfb-CreERtg/+;Foxf1fl/fl) is lethal (Cai et al, 2016), we used heterozygous mice for cancer studies (Pdgfb-CreERtg/+;Foxf1fl/+; abbreviated as endFoxf1+/−).