This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urinary tract, Subject name: Pathology
Which of the following is a metastasis suppressor gene in relation to prostate cancer? 
Select and explain. 
A. KAI -1, B. NM 23, C. KISS, D. p53
A: KAI -1
Answer: A: KAI -1 
Explanation: *Metastatic suppressor genes that acts without affecting primary tumor oKAI-1, CD44, MAPK4, nm23-H1, nm23-H2, KiSS-1 and BrMS1*Metastatic suppressor genes specific for prostate canceroKAI-1, CD44, MAPK4Ref: The Journal of Urology 2003 March;169(3):1122-33)