In the current study, a univariate analysis of the following variables was performed: Systemic disease (no/yes), age (<60/≥60 years-old), tumor grade (1/2,3 and unknown, with unknown grade corresponding to systemic disease at diagnosis), tumor size (≤20/>20 mm), axillary lymph node metastases (no/yes), ER status (negative/positive), serum HER2 (<30/≥30 ng/ml) and serum S100B (<0.072/≥0.072 μg/l). This evidence concerns the gene ESR1 and neoplasm.