TP53 mutation patterns in breast cancers: searching for clues of environmental carcinogenesis

Mutations in the tumour suppressor gene TP53 occur in about 30% of breast c ancers. We have used the IARC TP53 mutation database to analyse the pattern of mutations in breast cancers (1392 mutations). The global Pattern of mut ations is similar to the one of most other cancers, but there is an excess of transversions on G bases in tumours from Western (USA and Europe) as com pared to Eastern (Japan) countries. Moreover, the patterns of inherited TP5 3 mutations associated with breast cancer; differ from those of somatic mut ations. These differences support the hypothesis that a fraction of breast cancer mutations occur as a consequence of environmental exposures.