ESR1 and breast carcinoma: Women in whom we could not obtain a mammogram in an appropriate time window (see below) were more likely to have an earlier year of first breast cancer diagnosis (65% diagnosed in 1990–1996 versus 40% in 1990–1996) and to be missing ER status (14% versus 6%), and were slightly younger (mean age 45 years versus mean age 46 years).