Examination of cluster-specific marker genes showed that tumor ECs expressed a unique set of genes such as Col18a1 and Aplnr, but also shared a number of expressed genes with venous ECs, especially with PV, such as Cd63, Ehd4, and Cd200 (Fig. 2c and d, Supplementary Fig. 3a, and Supplementary Table 2). Here, CD63 is linked to neoplasm.