Although hemizygous deletion of KLF5 is highly frequent in human prostate cancer, no homozygous deletion was detected in hundreds of human cancer specimens [10], [11], [52], in contrast to the deletion of two other frequently deleted loci – NKX3-1 at 8p21 and PTEN at 10q23. Here, NKX3-1 is linked to Familial prostate cancer.