CD274 and neoplasm: In the primary tumor, infiltration of Th cells (CD3+CD8−FOXP3−), Treg cells (CD3+CD8−FOXP3+), CTLs (CD3+CD8+), and PD-L1-negative macrophages (CD3−CD163+PD-L1−) was found in the stroma surrounding the AE1/AE3-positive gastric cancer cells (Fig. 2a).