PECAM1 and melanoma: To investigate the changes in the EC transcriptome during the first steps of metastatic colonization, PECAM1+ (also known as CD31) PTPRC– (also known as CD45) ECs and labeled melanoma cells were isolated using flow cytometry from the lungs at 6 and 30 h after melanoma cell (or PBS as a control) injection and subjected to scRNASeq (Fig. 1a, b, Supplementary Fig. 2a–e).