ERBB2 and salivary duct carcinoma: Amplifications, high expression levels, and genomic aberrations of HER2 have been reported frequent in a subset of salivary duct carcinomas (17, 20) and several case studies using EGFR/HER2-TKi therapies including cetuximab, erlotinib, gefitinib, T-DM1, and trastuzumab on individual salivary gland cancer patients have been reported.