The lack of association between other breast cancer characteristics observed in the current study is in line with previous studies [33, 34], though an association between ERβ expression and lower-tumor grade has been reported, as have significant associations between ERβ and ERα, between ERβ and PR, and between ERβ and HER2 expression (all p < 0.01) [16]. This evidence concerns the gene ESR1 and neoplasm.