Interestingly, we observed that YY1 mRNA specifically increased in (ER)-positive/- progesteron receptor-positive (PR+)/-human epidermal growth factor receptor2-negative (HER2-) (ER+/PR+/HER2-) compared to the “triple negative” (ER-/PR-/HER2-) and “triple positive” (ER+/PR+/HER2+) BC subtypes (p = 0.27, Kruskal-Wallis test) (Figure 5). Here, ESR1 is linked to breast cancer.