BRCA1 and breast cancer: Notably, PVR was the most significantly up-regulated immunostimulator molecule in BRCA1-deficient breast cancers compared to BRCA-proficient breast cancers whereas IDO1 and LAG3 were the top most significantly up-regulated immunoinhibitor molecules in BRCA1-deficient breast cancers compared to BRCA-proficient breast cancers in both WSI and TCGA.