Familial breast cancer.

The genetic inheritance of familial breast cancer is complex and heterogeneous, i.e. it cannot be explained by one major susceptibility gene. It is likely that the chromosomal abnormalities and genetic lesions detected in the inherited syndromes will be implicated in the development of the more common sporadic breast tumours. Study of this important subgroup is essential to advance our understanding of the tumour biology of breast cancer and to develop adequate screening programmes for high risk young women.