CD4 and breast cancer: Immune cell subtypes that were enriched in BRCA1-deficient breast cancers relative to BRCA-proficient breast cancers in WSI and TCGA include cells involved in the adaptive immune response (activated CD4 T cells, activated CD8 T cells, regulatory T cells, T follicular helper cells, and γδ T cells) and innate immunity (myeloid-derived suppressor cell and natural killer cells) while CD56dim natural killer cells were depleted in BRCA1-deficient breast cancers relative to BRCA-proficient breast cancers (Fig 3A and 3B).