STAT3 and breast cancer: These findings are consistent with the following observations from the current study: miR-17-5p induced apoptosis in breast cancer cells (Figure 1); p53 expression was much higher in STAT3-knockout MCF-7 cells than in the control MCF-7 cells (Figure 4E); miR-17-5p overexpression promoted p53 expression in STAT3-overexpressing MCF-7 cells, but not in control MCF-7 cells (Figure 4F); and miR-17-5p-induced sensitization of breast cancer cells to Taxol-induced apoptosis requires STAT3 (Figure 4).