SOX2 and adenoid cystic carcinoma: Sox2 expression and gene amplification have been identified as common events in the head and neck [21, 22]; in the sinonasal region, amplification and/or overexpression of Sox2 has been demonstrated in squamous carcinoma (SNSCC), sinonasal undifferentiated carcinoma (SNUC), adenoid cystic carcinoma (AdCC), and intestinal type adenocarcinoma (ITAC) [22–24].