HER2 expression was found in 43% of salivary duct carcinomas (SDCs), 39% of carcinoma ex pleomorphic adenomas (CEPs), 17% of squamous cell carcinomas (SCCs), 13% of adenocarcinomas not otherwise specified (ADCs NOS), 6.7% of poorly differentiated carcinomas, 5.5% of mucoepidermoid carcinomas, 4.3% of myoepithelial carcinomas, 1.8% of epithelial-myoepithelial carcinomas, 0.45% of acinic cell carcinomas, and 0.15% of adenoid cystic carcinomas. The gene discussed is ERBB2; the disease is carcinoma.