ESR1 and neoplasm: In contrast, the proportions of patients with more aggressive tumor characteristics, including tumor size of at least 2 cm, positive lymph node status, adjusted AJCC sixth edition stage II to III, and tumor grade III to IV, gradually increased from ER-positive/PR-positive to ER-positive/PR-negative to ER-negative/PR-positive to ER-negative/PR-negative tumors (Table 1).