While the androgen receptor (AR) may play key roles to increase the tumor cell proliferation in several sex hormone-related tumors including prostate [1–6], bladder [7, 8], kidney [9, 10], breast [11], and liver [12–14], its impact on tumor cell invasion remains varied, as recent studies indicated that AR might function as a suppressor to decrease metastasis in prostate [1, 3, 4, 15–18] and liver [12–14] cancers, yet function as a stimulator to increase metastasis in bladder [7, 8, 19] and kidney [9, 10] cancers. This evidence concerns the gene AR and cancer.