ESR1 and cancer: In the step-up conditional logistic regression models, three variables were significantly more associated with ER+ BRCA-1 associated cancers than with ER+ sporadic controls: pure invasive ductal histology (RR 2.4, P = 0.03), 10 or more mitoses per 10 HPF (RR 5.0, P = 0.006), and absent or mild lymphocytic infiltrate (RR 10.2, P = 0.04).