PTEN and breast cancer: Among the candidate target genes, PTEN was the potential target for miR-940, IGF1R for miR-451a and miR-16-5p, and SRC for miR-17-3p (Fig. 7e), as aberrant signaling of PTEN, IGF1R, and SRC has been involved in trastuzumab resistance of breast cancer cells24–26.