Overexpression of cyclin B1 has been reported in various human tumors, such as breast cancer, cervical cancer, gastric cancer, colorectal cancer, head and neck squamous cell carcinoma and non-small-cell lung cancer [3-9] and its upregulation is closely associated with poor prognosis in various types of cancers including breast cancer [6,10,11]. This evidence concerns the gene CCNB1 and cancer.