ESR1 and neoplasm: The breast cancer patients with extraaxillary lymph node metastasis (N1) had lower proportion of the expression of ER (%) and PR (%) in tumor cells than N0 group (ER: 2 [0–80] vs. 80 [15–95]; PR: 1 [0–10] vs. 20 [0–45], p<0.001).