PTEN and breast cancer: Accumulating evidence has demonstrated that miR‐18a plays an oncogenic role in colon cancer, breast cancer and prostate cancer 30, 31, 32, and miR‐18a upregulation induces cell proliferation by stimulating cyclin D1 via the PTEN‐PI3K‐AKT‐mTOR signaling axis in oesophageal squamous cell carcinoma cells 33.