Elevated MYC signaling in human triple-negative breast cancers. (A) 149 primary tumors ordered by each tumor’s Pearson correlation to a 352 gene MYC signature centroid (P < 0.005; Fisher’s exact test). Triple-negative tumor samples are indicated with a red dot, whereas molecular subtypes are indicated with colored bars. (B) Correlation between MYC gene expression signature and breast cancer molecular subtypes. Relative MYC gene expression was based on each tumor’s Pearson correlation to the MYC gene signature. The error bars represent means ± SEM. P-values were calculated by two-tailed Student’s t test for each comparison. (C) Expression of multiple genes within the MYC signaling pathway is altered in triple-negative breast cancers. Schema shows various MAX-interacting genes that are deregulated and can positively or negatively modulate MYC transcriptional activity. Genes are shaded green if expression is suppressed in triple-negative versus receptor-positive tumors, and red if expression is increased in triple-negative tumors. MAX, P = 0.02; MYC, P < 0.0001; MYCN, P = 0.06; MXD4, P = 0.03 (two-tailed Student’s t test).