Low miR‐34b/c‐5p expression and high NK1R‐Tr expression were also significantly correlated with the clinicopathological characteristics of breast cancer, such as clinical stage and Ki67 expression, but not NK1R‐FL, indicating that the upregulation of miR‐34b/c‐5p and the downregulation of NK1R‐Tr may suppress the development of breast cancer. This evidence concerns the gene MKI67 and breast cancer.