MiR-144 was low-expressed in breast cancer tissues and cells. (A) The volcano plot showed the relationship between fold change and significance of miRNAs expression. (B) The heat map of 20 high-expressed miRNAs and 20 low-expressed ones in breast cancer. (C) The expression level of miR-144 in cancer tissues was significantly low. **P < 0.01, compared with adjacent tissues, number of adjacent tissue = 40, number of cancer tissue = 36. (D) Higher miR-144 expression was related to higher survival rate. (E) MiR-144 expression was down-regulated in breast cancer cells, especially in MCF7. *P < 0.05, compared with normal breast cells. (F) MCF7 cell line had the highest cell proliferation ability. *P < 0.05, **P < 0.01, compared with Hs 578Bst cell line.