The translating-ribosome affinity purification (TRAP) method was used to isolate the endothelial-specific mRNA fraction associated with eGFP-tagged ribosomes and the unbound (flow-through) fraction containing all remaining RNAs from the tumor tissue (including RNA from tumor cells, stroma and immune cells).32 Successful isolation of endothelial mRNA was confirmed by qPCR analysis, showing that the endothelial marker CD31 was highly enriched in the eGFP-immunoprecipitated fraction (Figure 3e). Here, PECAM1 is linked to neoplasm.