Epidermal growth factor receptor exon 20 p.S768I mutation in non-small cell lung carcinoma: A case report combined with a review of the literature and investigation of clinical significance.

Epidermal growth factor receptor (EGFR) plays a significant role in non-small cell lung cancer (NSCLC), the most prevalent form of lung cancer worldwide. Therefore, EGFR may be a useful molecular target for personalized therapy utilizing tyrosine kinase inhibitors (TKIs). Somatic activating EGFR mutations may be used to identify tumors sensitive to the effects of small-molecule EGFR-TKIs (gefitinib and erlotinib), and alternative, less frequently observed mutations, including the majority of mutations identified within exon 20, may be associated with a lack of response to TKIs. However, due to the comparative rarity of EGFR exon 20 mutations, clinical information concerning the association between EGFR exon 20 mutations and responsiveness to TKIs has been limited within the relevant literature, particularly for certain rare mutations, including p.S768I. The current study reports the case of a patient with NSCLC harboring a p.S768I mutation in the EGFR gene [a substitution at codon 768 of exon 20 (c.2303G>T, p.S768I)], as well as a mutation at codon 719, exon 18 (p.G719A). The relevant literature concerning this rare EGFR somatic mutation is also reviewed.