Low oestrogen receptor alpha expression in normal breast tissue underlies low breast cancer incidence in Japan

Among white Australians without breast cancer, the median of the percentage of oestrogen receptor cr. positive cells was 12% for women younger than 50 years and 17% for those 50 years or older; among Japanese women who had no breast cancer and are generally at low risk for this disease, the correspo nding values were both significantly lower and around 9%.