CD274 and ductal breast carcinoma in situ: There is a significantly higher proportion of CD3+ T cells, CD20 + B cells, macrophages and Tregs [102, 103] in DCIS tissue compared to adjacent normal tissue, while IDC tissue contains a significantly higher proportion of all T cells (helper, cytotoxic and regulatory), macrophages, B cells and PD-L1+ immune cells compared to adjacent DCIS tissue [102–104].