MSLN and mucoepidermoid carcinoma: The mucoepidermoid carcinoma (Fig. 1a and d), the adenoid cystic carcinoma (Fig. 1c and e), the non-specific adenocarcinoma (Fig. 1b) and some of the salivary duct carcinoma samples (Fig. 1f) included more MSLN positive cells in the cancer tissues.