ESR1 and breast cancer: On the contrary, women with ERα-positive BC have a significantly higher survival probability when the tumor expresses high levels of ATP1A1 or ATP1B1 (Figure 4A,F; see also Supplementary Table S4) while no significant changes in RFS of women with ERα-positive BC have been evidenced considering the ATP1A2 mRNA expression (Figure 4D; see also Supplementary Table S4).