Fig. 7: Schematic summary depicting the subtype and race-specific differences in BC immune landscape.

TNBC exhibit overall higher immune cell infiltration, specifically having a greater abundance of B-cells, Tregs, Th1, and CD8+ T-cells, compared to the non-TNBC. Pathway analysis of differentially expressed genes show activation of immunosuppressive pathways despite greater immune cell infiltration. TNBC from White patients have a higher presence of Th1 and CD8+ T-cells in the TME than those from Black patients, while non-TNBC from Black patients exhibit a higher accumulation of NK and Treg cells but lower DC, compared to that in White patients. Black patients show reduced immune activation regardless of molecular subtype. Higher TAM and lower T-cell infiltration in all BC patients, and lower TILs in White patients, are indicative of the metastatic disease.