TP53 is the gene most often mutated in human cancer, and several studies have shown that loss of one allele in the germ line leads not only to a much increased risk of cancer but also to a decreased AR in lymphoid cells from both rodents (Clarke et al, 1993; Lowe et al, 1993) and humans (Camplejohn et al, 1995, 2000). This evidence concerns the gene AR and cancer.