These data suggested that EGFR constitutes an important therapeutic target in breast cancers and have prompted investigators to consider gefitinib (ZD1839, Iressa®), a reversible small molecule inhibitor of the EGFR tyrosine kinase, for treatment of HER2 overexpressing and EGFR co-expressing breast malignancies [19]. This evidence concerns the gene ERBB2 and breast carcinoma.