ESR2 and breast cancer: Although FUL has shown a moderate therapeutic effect against triple-negative BC (ERα-/ERβ+) and inhibition of hormone responsive (ERα+/ERβ+) BC via upregulation of ERβ mRNA and protein expression levels (Mishra et al., 2016), the lack of a significant effect on the time course of tumor growth after cyclic FUL regimens (oral administration of 5 mg/kg BW/week) in the present study could be due to the poor oral bioavailability of FUL (Robertson, 2007).