ESR1 and neoplasm: Multivariable analysis including these factors revealed that tumor size (p < 0.0001), lymph node metastasis (p < 0.0001), tumor grade (p = 0.014), ER status (p = 0.024), chemotherapy administration (p = 0.0021), and CEA (p = 0.047) and CA15-3 (p < 0.0001) levels were independent prognostic factors (HR 1.520, 95% CI 1.005–2.245 for CEA high; HR 2.088, 95% CI 1.457–2.901 for CA15-3 high) (Table 3).