ESR1 and breast cancer: Van den Brandt and Schulpen investigated the impact of adherence to a Mediterranean-style diet in over 2000 cases of breast cancer in the Netherlands, and found that adherence to the dietary pattern in estrogen receptor negative (ER-) and ER-/progesterone receptor negative (PR-) postmenopausal breast cancer decreased incident risk [24] These results were confirmed by a meta-analysis.