,
reflecting different rates of tobacco exposure. In contrast, female
breast cancer is the most frequently diagnosed cancer in most countries,
reflecting less modifiable internal hormonal influences. 5-10% of these
cases arise from heritable causes such as susceptibility to breast
cancer and ovarian cancer conferred by cancer susceptibility genes such
as BRCA1 and BRCA2 . A typical woman’s lifetime risk of
breast cancer is about 12%, rising to 70% for a woman carrying one of
these
mutations.