[Comparative Analysis of EGFR Gene Mutations (exon 20) in Sinonasal Papillomas of Inverted and Oncocytic Types]

Objective: To provide a comparative description of the gene (exon 20) based on the results of Sanger sequencing in sinonasal papillomas of inverted and oncocytic types.

Material And Methods: Sanger sequencing of the gene (exon 20) was performed in 83 cases of sinonasal papillomas, of which 17 were of OSP and 66 were ISP cases. In 20 cases, an additional immunohistochemical study with an antibody to EGFR was also performed.

Results: When sequencing by Sanger of exon 20 of the gene in the ISP group, missense mutations were identified in 16 out of 66 cases, leading to a change in the value of the coding sequence of the gene, ultimately determining the formation of a different amino acid; this type of mutation was not identified in the OSP group. The most common mutation was at position 2622 in the form of G to A transition: in 47 cases of ISP (70%) and in 12 cases of OSP (71%). This mutation was synonymous and did not lead to an amino acid replacement in the synthesized protein. Thus, we did not find any significant differences in exon 20 of the EGFR gene between the ISP and OSP groups. In the ISP group, in 48 of 66 cases, multiple and single point mutations were noted, which we characterize as genetic heterogeneity.