ERBB2 and metastatic neoplasm: 39 patients (97.5%) had been treated with trastuzumab in the (neo)adjuvant or metastatic setting; 6 patients had received pertuzumab and trastuzumab as first-line therapeutic regimen; 21 patients (52.5%) received anti-HER2 therapy with TKI (lapatinib) for their metastatic disease; none of them was previously treated with TDM-1.