HECTD3 and neoplasm: To further confirm that Hectd3 deficiency inhibited tumor metastasis specifically through endothelial cells, we generated C57BL/6 strain Hectd3 floxed mice (Supplementary Fig. 6o–q) and crossed these mice with Tie2-Cre mice to obtain Tie2-Cre+;Hectd3fl/fl mice in which Hectd3 was specifically deleted in the endothelium (Fig. 6f).