NPY1R gene expression was significantly reduced in EDR, TamR, and FulR derivatives of MCF7 (Fig. 4A), T47D (Fig. 4B), and ZR75-1 (Fig. 4C) ER+ BC cell line models compared to the parental cells (p < 0.05, One-way ANOVA, Tukey test). This evidence concerns the gene ESR1 and breast cancer.