Suppression of the NEK2 expression with siRNA inhibited cell proliferation and induced cell death of breast cancer, cholangiocarcinoma, colorectal cancer, multiple myeloma, hepatoma and prostate cancer cells in vitro, and led to a reduction of tumor size in xenograft-nude mouse model [13, 15, 17, 20–23]. This evidence concerns the gene NEK2 and breast carcinoma.