One of the most promising candidates as target for molecular analysis as an inherited breast cancer predisposition gene is the p53 tumour suppressor gene: it is frequently somatically mutated in a wide range of human cancers including breast cancer (Harris and Hollstein, 1993); germline mutations lead to an increased risk for developing diverse malignancies, including 25–30% of breast cancer cases (Bukholm et al, 1997), in the context of Li–Fraumeni syndrome (LFS) or LFL – Li–Fraumeni-like syndrome (Varley, 2003). The gene discussed is TP53; the disease is breast carcinoma.