STAT3 and breast cancer: For comparison, STAT3 (BC: r = 0.18420, P < 0.0001; TNBC: r = 0.18274, P = 0.009) and MYC (BC: r = 0.119, P < 0.0001; TNBC: r = 0.018, P = 0.789), both known transcriptional activators of CD274 [12, 36], showed similar or lower correlations (Fig. 1B, C; Supplementary Fig. S2A–C).