They modulate cell behaviours, proliferation, differentiation and apoptosis by simultaneously targeting multiple genes.2, 3, 4, 5 In breast cancer, the miR‐34 family is often lost or poorly expressed and is a potential tumour suppressor gene.4, 6 MiR‐34 may inhibit breast cancer cell proliferation by suppressing c‐Myc and the phosphatase activities of ERK and AKT.7, 8 Moreover, miR‐34 induces cell cycle arrest and apoptosis in breast cancer.4, 9 These findings strongly suggest that miR‐34, as a tumour suppressor, may be a new therapeutic target and intervention strategy against breast cancer. This evidence concerns the gene MYC and breast cancer.