EGFR and BRAF mutations in inverted sinonasal papilloma — a more complex landscape?

AbstractInverted (Schneiderian) sinonasal papilloma (ISP) is a neoplasm derived from mucosa of the sinonasal tract characterized by local aggressive growth, a tendency to recur and an association with sinonasal carcinoma. The etiology of ISP remains unclear. Recently, identical mutations in exons 19 and 20 of the oncogeneEGFR were reported in ISP and ISP-associated sinonasal carcinoma. Nevertheless, it remains unclear whether recurring ISPs show identicalEGFR mutations at different time points or whether these mutations are identical throughout the respective ISP sample. We used Sanger sequencing to test 60 formalin-fixed paraffin embedded ISP samples from 40 patients regarding mutations in exons 19 and 20 ofEGFR—together with exon 15 ofBRAF. Overall, 32 samples of 22 patients showed a mutation inEGFR exon 20, whereas 28 samples of 18 patients showed none. No mutation inEGFR exon 19 was found in any sample. Four samples of four patients showed aBRAF exon 15 mutation. Interestingly, samples of four patients exhibited genetic heterogeneity, enabling us to report this in ISP for the first time.
Source: Virchows Archiv - Category: Pathology Source Type: research