ESR1 and breast cancer: Another study tried to assess the impact of approximately 1 to 5 grams per day of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) over a 12-month period on the fatty acid and oxylipin profiles in breast adipose tissue among survivors of estrogen receptor and progesterone receptor-negative (ERPR(-)) BC (67).