After NSDHL knockdown by transfection of short interfering RNA into human breast cancer cell lines (MCF-7, MDA-MB-231 and BT-20) and human breast epithelial cell line (MCF10A), cell proliferation assay, cell cycle analysis, three-dimensional cell culture, clonogenic assay, transwell migration and invasion assays, and wound healing assay were performed. The gene discussed is NSDHL; the disease is breast cancer.