It has long been recognized that some very rare forms of cancer, such as retinoblastoma
and neuroWbromatosis, are caused by inherited genes. It is only within the
last few years, however, that rapid progress has been made in understanding the
role that inherited genes also play in determining a proportion of the more
common cancers, including breast, colorectal and ovarian cancer. Although there
is still uncertainty about the precise contribution of inherited predisposition genes
to the incidence of these cancers, the available evidence suggests that breast,
colorectal and ovarian cancer have a number of common genetic features.