The distribution of estradiol in the sera of normal Caucasian, Chinese, Filipina, Hawaiian and Japanese women living in Hawaii.

Mean concentrations of sex-hormone-binding-globulin (SHBG) and the percentage distribution of estradiol between the non-protein-bound, albumin-bound and SHBG-bound fractions were not different in Caucasian, Hawaiian, Chinese, Japanese and Filipinas living in Hawaii. The widely varying incidence rates for breast cancer are therefore not explained by variations in the availability of estradiol.