In another work, they also found four CAF populations in breast cancer, but their markers were differentially expressed, CAFS1 and CAFS4 (FAP, CD29, αSMA, PDGFRβ), CAFS2 (αSMA, PDGFRβ), CAFS3 (CD29, PDGFRβ). Here, PDGFRB is linked to breast carcinoma.