ESR1 and neoplasm: For example, by assaying 3800 tumor samples, significant inverse correlations with age and biomarkers of tumor growth and genetic instability (e.g., Ki-67 and p53 positivity) and growth factor receptor over expression (e.g., ErbB2+ or EGFR+) were shown (all P = 0.05), and among ER+ tumors, ER expression was significantly positively correlated with age (P < 0.0001).