We assembled a clinically well-characterized cohort comprising the most common sinonasal carcinomas, namely SCC, sinonasal undifferentiated carcinoma (SNUC), carcinoma associated with an inverted papilloma (INVC), adenocarcinoma (AD) and adenoid cystic carcinoma (ACC) and assessed for SOX2 amplification and protein expression status. This evidence concerns the gene SOX2 and sinonasal undifferentiated carcinoma.