In Taiwan, about 70% of new incident prostate cancer patients have localized disease. Most patients were detected by PSA screening. Among them, many had low-risk PC, which is very likely latent in nature, progresses slowly, and rarely leads to death. Most patients died of other causes, such as other cancers, cardiovascular diseases, and diabetes mellitus. Many guidelines recommend that active surveillance (AS) or watchful waiting (WW) is a good option for low risk patients to avoid overtreatment-related complications. However, 30% of patients on AS will finally need definitive treatments due to disease progression within 10 years. We hypothesize that there are differential gene expressions between progressive and non-progressive tumors. If we can identify key genes or pathways that are responsible for progression of low risk PC to higher risk diseases, PC progression could be reduced substantially by regulating these genes or pathways and maintain long-term cancer latency to control non-metastatic PC. In light of the high prevalence rate of latent PC in adult men, the strategy is in fact the best strategy for preventing clinical PC.