ERBB2 and salivary duct carcinoma: The prevalence of HER2-positivity, assigned by immunohistochemistry (IHC) and/or gene amplification by fluorescence in situ hybridisation (FISH), is reported in up to 13%, 39%, and 43% of adenocarcinoma NOS, carcinoma ex-pleomorphic adenoma, and salivary duct carcinoma, respectively [6].