PDGFC and neoplasm: As METABRIC is a bulk tumor analysis, it is not possible to differentiate between tumor cell and stromal PDGFC expression; however, single-cell RNA-seq analysis of 26 human breast cancers21 demonstrated comparable PDGFC expression across ER+ and ER− tumor cells, with ER+ cells expressing markedly higher levels of PLAT (Extended Data Fig. 5b).