PECAM1 and neoplasm: Flow cytometric analysis of single-cell suspensions at day 11 showed that the LCMV-NP protein was broadly distributed with high expression in PDPN-expressing FSCs and in B16F10 tumor cells (marked by the mCherry reporter), while a significantly lower proportion of CD45+ immune cells and CD31+ blood endothelial cells harbored the viral antigen (Fig. 3b, c, Supplementary Fig. 3a, b).