CHARGED AMINO ACIDS FREE
The majority of EGFR mutation-positive NSCLC patients respond to EGFR-tyrosine kinase inhibitors (TKIs) and are expected to have a prolonged progressive free survival (PFS) and overall survival (OS) ( 1, 2). These 11 polar amino acids are divided into 5 polar charged amino acids (arginine, histidine, lysine, glutamic acid, and aspartic acid) and 6 polar uncharged amino acids ( 10). There are twenty types of amino acids, 9 of which are nonpolar and 11 are polar ( 10). Moreover, NGS allowed the investigation of the amino acids of compound mutations in detail ( 10). Recently, the new technology of next-generation sequencing (NGS) allowed researchers to investigate in detail whether compound mutations co-exist in patients with common mutations ( 4, 7- 9). As there are many types of compound mutations, each in a small number of patients, only a few studies have examined the treatment response and survival of patients with compound mutations as a whole group ( 5). These patients have been treated as those with compound mutations, which are defined as double nonsynonymous mutations in the EGFR gene ( 5, 6).
There are many types of uncommon EGFR mutations ( 2- 4) and, although rare, there are patients with both common and uncommon mutations at the same time ( 5, 6). Other types of mutations are collectively referred to as uncommon or minor mutations ( 2, 3). The most common epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) patients are exon 19 deletions and exon 21 L858R mutation ( 1). Detailed examination of EGFR gene information might contribute to the understanding of TKI response duration. Conclusion: Patients with ‘polar charged amino acids in compound mutations’ might have favorable prognosis than those without them. In uni- and multivariate analysis, ‘poor performance status’ and ‘polar charged amino acids in compound mutations’ were significant favorable factors in OS. There were no statistically significant differences in the clinical background factors examined in these two groups of patients. Results: Among the 20 patients examined, 5 patients had polar charged amino acids in compound mutations and 15 had not. We investigated prognostic significance of these amino acids in compound mutations in progression free survival (PFS) and overall survival (OS) in patients treated with first-line afatinib.
For clinical information, the medical records were retrospectively investigated. Patients and Methods: EGFR gene mutations were investigated using nonoverlapping integrated read sequencing system (NOIR-SS) in pathological specimens of 20 EGFR-mutated NSCLC patients. With this background, a retrospective study was conducted aiming to clarify the prognostic significance of these amino acids in complex mutations in NSCLC patients with common EGFR mutations. Several preclinical studies have suggested the involvement of polar charged amino acids in the treatment of EGFR mutations and EGFR-tyrosine kinase inhibitors (TKIs). Background/Aim: Next-generation sequencing (NGS) has recently made it possible to investigate polar charged amino acids in compound mutations in the epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC).