As combinations of immunomodulatory molecules, including PD-L1 and PD-1, are expressed by tumour and tumour-infiltrating immune cells to shape the landscape of the tumour microenvironment, we investigated whether the differences in expression of immunomodulatory molecules observed between BRCA1- and BRCA2-deficent breast cancers correspond to distinct patterns of immune filtrates. The gene discussed is BRCA1; the disease is breast cancer.