MiR‐34 s serve as breast cancer suppressors by regulating hundreds of downstream targets.35, 42, 43 From our previous studies, the two isoforms of NK1R, NK1R‐FL and NK1R‐Tr, are involved in different biological actions in breast cancer: here, we show that NK1R‐Tr was markedly upregulated and that NK1R‐FL was markedly downregulated in breast cancer cells and tissues. This evidence concerns the gene TACR1 and breast cancer.