ESR2 and breast cancer: The post hoc analysis revealed a significant reduction in oestrogen receptor type 2 (ESR2) protein level in the AgNano + BC group compared to the BC group (p = 0.039; 0.258 ng/mg protein (95% CI [0.249–0.266]) versus 0.324 ng/mg protein (95% CI [0.293–0.354]), Figure 3B).