FLT1 and neoplasm: Based on marker genes for every cluster (Additional file 2: Table S5), we revealed one set of lymphatic endothelial cells (cluster 9, TFF3 +) and nine sets of vascular endothelial cells (FLT1 + , Fig. 5b): One was mostly interface-derived (clusters 2; HLA-DQA2 +) and three were mostly tumor-derived (clusters 4, 6 and 8; ROBO1 +) (Additional file 1: Figure S2e).