SP1 and breast cancer: Previous reports indicate that MIR539 expression is downregulated in breast cancer tissues and cell lines (Guo et al., 2018), and MIR539 acts as a tumor suppressor by targeting epidermal growth factor receptor (Guo et al., 2018), specificity protein 1 (Cai et al., 2020), or laminin subunit alpha 4 (Cai et al., 2020) expression.