FAP and breast cancer: Lastly, using TGM2 co-expression data of breast invasive carcinoma patients, CAF markers ACTA2, FAP, PDGFRA, and PDGFRB were significantly correlated with TGM2 expression, indicating that Tg2 expression correlates with fibroblast activation in breast cancer patients (Cerami et al., 2012; Gao et al., 2013; Figure 7d).