ERBB2 and adrenal cortex carcinoma: However, partial response to trastuzumab was reported for a mucoepidermoid carcinoma with HER2 3+ immunostaining (Haddad et al, 2003) and prolonged tumour progression to lapatinib was documented in three non-ACC tumours with HER2 amplification and 3+ staining for EGFR and HER2 (Vidal et al, 2009).