ESR1 and breast cancer: However, as opposed to the 10 genes upregulated in both breast tumors and normal breast tissues (Figure 6d,e), a low expression of 21 genes was associated with the reduced OS of BC patients compared with the high expression of those 21 genes for all tumor subtypes (Figure 6g) as well as for ER-positive (p-value = 0.00424, n = 560) and LN-positive (p-value = 0.00056, n = 215) subtypes.