EZH1 and breast cancer: Nevertheless, another study elaborated that EZH1 was downregulated in SUM159 BC cells (Liu et al., 2012), which could be induced by miRNA-93 expression; miRNA-93 has proved to be upregulated in the MDA-MB-231 cell line and ER- or PR-negative BC patients (Kolacinska et al., 2014; Li et al., 2017).