In breast cancer cells, miR-17-5p negatively regulates the expression of phosphatase and tensin homolog, PTEN (Li et al., 2017), and the activation of PTEN inhibits the PI3K/AKT/mTOR signaling pathway (Guo et al., 2015), suggesting that the overexpression of miR-17-5p may promote the PI3K/AKT/mTOR signaling pathway. The gene discussed is MTOR; the disease is breast cancer.