ESR1 and breast carcinoma: Beside CXCR4 expression, a phenotypic characterization of the cells from the primary cultures was performed, by analyzing the expression of common mammary lineage markers (CK14, CK18, EMA, ER-α), or proteins (EGFR and HER-2/neu) overexpressed in mammary carcinoma conferring malignant behaviour (Figure 5).