Other genes that predispose to breast cancer, such as TP53 (associated with Li-Fraumeni and Li-Fraumeni-like syndromes, LFS/LFL) (Li and Fraumeni, 1969; Birch et al., 1994; Eeles, 1995) PTEN (associated with Cowden's syndrome) (Eng, 1997) and CHEK2 (associated with hereditary breast and colon cancer syndrome, HBCC) (Meijers-Heijboer et al., 2003) have been identified and are thought to have important, albeit lower, contributions to the phenotype (Li et al., 1988; Vahteristo et al., 2002). Here, TP53 is linked to Li-fraumeni-like syndrome.