Consistent with this finding, Mechta-Grigoriou et al. have identified four subtypes of cancer-associated fibroblasts (CAF-S1-4) in human breast cancer and high-grade serous ovarian cancers by fluorescent-activated cell sorting, and found CAF-S1 subtype, characterized by elevated FAP expression, which is responsible for generating an immunosuppressive TME by accumulating CD4+CD25+ T cells and enhancing their differentiation to Tregs [45, 46]. The gene discussed is FAP; the disease is breast carcinoma.