ESR1 and breast cancer: The highest correlations were observed for PDL1 expression in LC (Spearman’s rho = 0.797, p = 0.00004), HER2 expression in BC (Spearman’s rho = 0.798, p = 6.9 × 10−10), and ESR1 expression in BC (Spearman’s rho = 0.777, p = 3.8 × 10−9), while correlation with PGR in BC was lower yet still highly statistically significant (Spearman’s rho = 0.653, p = 4.9 × 10−6; Figure 4).