Low oestrogen receptor α expression in normal breast tissue underlies low breast cancer incidence in Japan Original Research Article

Among white Australians without breast cancer, the median of the percentage of oestrogen receptor α 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 corresponding values were both significantly lower and around 9%.