Many studies have shown downregulation, mutation, or inactivation of KLF6 in most cancers, including nasopharyngeal carcinoma [11], astrocytic glioma [12], pituitary tumors [13], gastric cancer [14], colorectal cancer [15], breast cancer [16], hepatocellular carcinoma [17], and prostate cancer [18]. The gene discussed is KLF6; the disease is prostate cancer.