ESR1 and ductal breast carcinoma in situ: Meta-analysis demonstrated significant associations between fine linear calcifications and high-grade DCIS [pooled odds ratio (pOR), 4.92; 95% confidence interval (CI), 2.64–9.17], (comedo)necrosis (pOR, 3.46; 95% CI, 1.29–9.30), (micro)invasion (pOR, 1.53; 95% CI, 1.03–2.27), and a negative association with estrogen receptor positivity (pOR, 0.33; 95% CI, 0.12–0.89).