Conditional knockout of the LTβR in ECs (Cdh5CreERT2xLtbrfl/fl referred to as Ltbrfl/fl) caused a reduction of PNAd, CCL21, and ICAM1 expression in BECs (Figures 5A and S5A), similar to the dedifferentiation observed in HECs during lymphoma challenge. Here, ICAM1 is linked to lymphoma.