To examine the correlation of miR‐34 and NK1R in breast cancer, MDA‐MB‐231 and MCF‐7 cells, which express high level of NK1R‐Tr, were transfected with miR‐34a‐3p, miR‐34a‐5p, miR‐34b‐3p, miR‐34b‐5p, miR‐34c‐3p, miR‐34c‐5p mimics and inhibitors. The gene discussed is TACR1; the disease is breast carcinoma.