TGFB1 and cancer: Based on our finding that miR-196a-3p mimics inhibit the metastasis of breast cancer cells, which was reinforced by knockdown of NRP2 and antagonized by TGF-β1 stimulation, and previous reports that NRP2 acts as an oncogene to promote metastasis in cancers such as breast cancer [25], esophageal squamous cell carcinoma [26], and melanoma [27], we hypothesized that miR-196a-3p and its downstream target NRP2 is involved in TGF-β-induced cell migration and invasion in breast cancer.