Considering the demonstrated significance of CHEK1 and miR‐195‐5p for the prognosis of patients treated with classical chemotherapy and their verified miRNA‐mRNA regulatory relation in the present study, we hypothesized that the downregulation of CHEK1 by miR‐195‐5p could increase the efficacy of anthracyclines in luminal BC. The gene discussed is CHEK1; the disease is breast cancer.