Sinonasal squamous cell carcinoma and EGFR mutations: a molecular footprint of a benign lesion.

AIMS: Molecular targeted therapy against EGFR kinase domain mutations has been successfully established for lung cancer. These mutations have now also been reported in head and neck tumours, particularly in inverted sinonasal papillomas (ISPs). The aim of this study was to clarify the spectrum of EGFR mutations in head and neck squamous cell carcinomas and papillomas.

METHODS AND RESULTS: We examined EGFR mutations in 288 head and neck squamous cell carcinomas and 58 head and neck papillomas or polyps. EGFR mutations were detected in 24 (30%) of 80 sinonasal squamous cell carcinomas (SNSCCs) and in 19 (90%) of 21 ISPs. Notably, 15 (88%) of 17 SNSCCs that developed along with ISPs harboured EGFR mutations in both components, whereas EGFR mutations were detected in nine (14%) of 63 SNSCCs without any papilloma component. Analysis to detect other known driver oncogene mutations - KRAS, BRAF and HER2 - was also performed; none of these mutations was detected in SNSCCs. The other 208 non-sinonasal carcinomas and 37 non-ISP head and neck papillomas or polyps did not harbour EGFR mutations.

CONCLUSIONS: Taken together with the specific involvement of EGFR mutations in ISP, a molecular benign lesion trail suggests that 26 (33%) of 80 SNSCCs developed in association with an ISP. SNSCCs with EGFR mutations may be biologically distinct among head and neck cancers.