MUCL1 and breast cancer: We observed a correlation (r = 0.36; P < .001) (eFigure 5I in Supplement 1) between gene expression profiles of TNBCs of younger African American patients and QNBC tumors of 161 patients in the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) cohort (eFigure 5I in Supplement 1).20 For example, while MMP7 and FOXC1 genes were upregulated, MUCL1 and FOXA1, factors that maintain mammary cell differentiation, were downregulated in both groups.