ERBB2 and breast cancer: CDH1 gene expression was significantly (p < 0.001) higher in stages 3 and 4 in all BRCA patients than in other clinical stages and Luminal A breast cancer subtype; but a non-significant difference in BRCA-Basal patients; a significant (p < 0.01) or (p < 0.05) difference in stage 4 in BRCA–Her2 and in stage 3 and 4 in BRCA-LumB patients.