To further investigate the effect of miR‐22 on tamoxifen resistance, we analyzed patient data from a public database and found that in ERα‐positive (tamoxifen‐sensitive) breast cancer patients, the group with high miR‐22 expression had a poorer prognosis than the group with low miR‐22 (Figure 4I; Figure S3I, Supporting Information). This evidence concerns the gene ESR1 and breast cancer.