Our study showed that the TNBC cells showed a lower expression level of miR‐200b than other breast cancer cells and normal breast cells as previously described.30 Furthermore, we explored the interaction of MYC, DNMT3A and miR‐200b in TNBC cells, and revealed that miR‐200b was epigenetically suppressed by MYC and DNMT3A‐mediated promoter methylation. This evidence concerns the gene DNMT3A and breast cancer.