Fig. 6: Ligand-Receptor Interactions and ESG Analysis in Black American (BA) and White American (WA) Niches Reveal Distinct Mechanisms of Tumor Progression and Immune Suppression.

a Ligand-receptor interactions derived from ESGs associated with the BA niche (BA-community 1) reveal the activation of multiple tumor-promoting pathways, including those involving cell surface proteins, adhesion molecules, extracellular matrix components, endothelial cells, and key signaling pathways such as platelet-derived growth factor receptor (PDGFR), Transforming Growth Factor beta (TGF-ß), WNT, Notch, Thrombospondin, and Placental Growth Factor (PGF). In contrast, ligand-receptor interactions in the WA niche (WA-community 1) are dominated by cytokine activities and pathways related to T-cell exhaustion. b Normalized frequencies of ligand-receptor interactions in the BA-niche, analyzed using ESGs from BA-community 1, are presented in a matrix format with ligands (rows) and receptors (columns). c Normalized frequencies of ligand-receptor interactions in the WA-niche, analyzed using ESGs from WA-community 1, are similarly presented. d Average expression of genes associated with T-cell exhaustion³¹ in WA-community 1 in WA and BA TNBC tissues. The expression of T-cell exhaustion-related genes was significantly higher in WA TNBC compared to BA TNBC, with significance computed using a T-test. e Quantification of the average number of spots containing genes associated with T-cell exhaustion in N = 10 BA and N = 10 WA TNBC spatial transcriptomics (ST) samples³⁰. Each ST sample is an independent TNBC patient and contains between 1500 and 2500 spots. The number of co-localized spots was significantly higher in WA TNBC compared to BA TNBC, with significance determined using a Kolmogorov-Smirnov test. Box plots represent the median (center line), interquartile range (25–75%; bounds of the box), and whiskers extending to the 1.5 IQRs. Points that fall outside this range are displayed independently. Source data are provided as a Source Data file.