Interestingly, another clinical study enrolling 240 Norwegian early breast cancer patients showed strong and significant associations between the overexpression of miR-25, miR-18a/b, miR-106b, and miR-505 with high proliferation, estrogen receptor negativity and cytokeratin 5/6 positivity of cancer [86] (Table 5). This evidence concerns the gene ESR1 and breast cancer.