CD274 and neoplasm: For example, TGF-β upregulates tumor cell and TAMs PD-L1 expression through the AKT/NF-kB or AKT/β-catenin (β-catenin plays a critical role in polarizing macrophages to TAMs, resulting in epithelial-mesenchymal transition and tumor progression) pathway after binding to its receptor [121, 122].