ESR1 and neoplasm: There was a positive correlation between ESR1 and EFNA1 gene expression in BRCA-Lum-A patients, corroborated via the EFNA1 differential gene expression level being higher in the tumor than the normal tissues and a negative ER status as well as significantly higher EFNA levels in stages 3 and 4 in all BRCA patients and stage 4 in BRCA-LumA patients, and a significant difference in stage 4 in BRCA-Her2 and BRCA-LumB patients, but not significance in any stage in BRCA-Basal patients.