To explore the relationship between epidermal growth factor receptor (EGFR) gene19 th and 21 th exons mutation and clinicopathological features, prognosis of lung adenocarcinoma.

The clinical data and specimens of 100 patients who were pathologically confirmed with lung adenocarcinoma from January 2017 to June 2018 were retrospectively analyzed. PCR-ARMS technique was applied to detect the mutation of EGFR gene 19 th and 21 th exons. The relationship between EGFR gene mutation and clinicopathological features, prognosis was analyzed.

Among the 100 lung adenocarcinoma specimens, there were 47 cases with EGFR mutation, with mutation rate of 47.00%, Among them, there were 20 cases (42.55%) with 19 th exon mutation, including 6 types of mutations, which were mainly on nucleotide framework deletions. And the most common type was delE746-A750 mutation with 15 bp deletion within nucleotide 2234-2248 (11 cases, 55.00%). And there were 27 cases (57.45%) with 21 th exon mutation, including 5 types of mutations, all of which were base substitution mutations. The most common type was L858R where T was replaced by G at 2573 locus (17 cases, 62.96%). The mutation rates of EGFR19 and EGFR21 in patients with female gender, without smoking history, and with clinical staging at stage I were higher than those in the other patients (P<0.05). Logisitic regression analysis showed that gender, smoking history, tumor diameter and clinical pathological stage were related with mutation of EGFR19 and EGFR21. All the 100 patients with lung adenocarcinoma were followed up effectively. The 2-year progression-free survival (PFS) rate and overall survival (OS) rate in EGFR19 mutation patients and non-mutation patients were (80.00%, 85.00%) and (65.00%, 73.75%), respectively. The 2-year PFS rate and OS rate in EGFR21 mutation patients and non-mutation patients were (81.48%, 92.59%) and (63.01%, 69.86%), respectively. The 2-year survival rate in patients with female gender, early clinical staging, without lymph node metastasis, and with EGFR21 mutation was lower than that in the other patients (P<0.05). Logisitic regression analysis showed that male gender, late clinical staging, lymph node metastasis and EGFR21 non-mutation were independent risk factors of poor prognosis of lung adenocarcinoma patients.

The mutations of EGFR gene 19 th and 21 th exons in lung adenocarcinoma are related to gender, smoking history, tumor diameter and clinical stage, which are are also effective methods for predicting prognosis.