An Analysis of EGFR Mutations among 1506 Cases of Non-Small Cell Lung Cancer Patients in Guangxi, China

<div><p>An association between epidermal growth factor receptor (EGFR) and clinical characteristics of non-small cell lung cancer (NSCLC) was reported ten years ago. In addition, a different type of relationship was seen in different ethic races. However, the relationship between these factors is not well understood in the Guangxi province. Up to now, there are only very limited data on the association of TTF1/EGFR protein positivity and EGFR mutation status in NSCLC. This study aims to investigate the role of EGFR gene mutation status on the clinical characteristics and the relationship with TTF-1/EGFR protein positivity of patients with NSCLC in Guangxi, China. 1506 samples from different patients with NSCLC were detected by amplification refractory mutation system for 29 hotspot mutations. Analysis of the relationship between clinical characteristics and EGFR mutation status was performed by using the crosstabs Chi-square and SPSS 21.0 software. Of 1506 samples, 537 (35.7%) revealed tyrosine kinase inhibitor (TKI) sensitive EGFR mutations with 27 (1.8%) cases harboring TKI resistant EGFR mutations or union co-existing EGFR-TKIs sensitive mutations. EGFR-TKIs sensitive mutations were not significantly associated with age and TNM-M stage (<i>P</i> = 0.863; <i>P</i> = 0.572, respectively). However, they were significantly associated with p-stage, TNM-T stage and TNM-N stage (<i>P</i> = 0.011, <i>P <</i> 0.001, <i>P</i> = 0.036, respectively). Immunohistochemical studies revealed that TTF-1 and EGFR protein expression level were all associated with EGFR mutation status (<i>P</i> < 0.001, <i>P</i> = 0.002, respectively). Of the 537 EGFR-TKIs sensitive mutation cases, the rates of exon 19-del, 18 G719X point, exon 21 L858R and L861Q points were 54.6, 0.9, 42.3 and 0.9%, respectively. EGFR TKI-sensitive mutations commonly occur in female, non-smoking and adenocarcinoma patients. The p-stage, TNM-T stage, TNM-N stage, EGFR and TTF-1 protein expression levels have close relationships with EGFR mutation status.</p></div

Frequency of EGFR-TKI resistant or co-exiting^* mutations.

<p>Frequency of EGFR-TKI resistant or co-exiting^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0168795#t004fn001" target="_blank">*</a>} mutations.</p

Characteristics of patients.

<p>Characteristics of patients.</p

Frequency of EGFR-TKI sensitive mutations.

<p>Frequency of EGFR-TKI sensitive mutations.</p

Immunohistochemical staining of EGFR protein expression in non-small cell lung cancer.

<p>A: EGFR negative (×100); B: EGFR negative (×400); C: EGFR positive (×100); D: EGFR positive (×400).</p