Analysis On The EGFR Mutation Test Results Of Monocentric 100 Sequential Patients With Primary Bronchogenic Carcinoma

Objective: To collect pathology specimens form 100 sequential patients with lung cancer after radical resection of pulmonary bronchogenic carcinoma in our single center, and EGFR mutations were detected. In this study, we investigated epidermal growth factor receptor(EGFR) mutation characteristic(mutation sites and frequency) and its relationship with clinical features(histological type, gender, smoking status, clinical stage, degree of differentiation) in primary lung cancer.Methods: We collected surgical specimens from 100 consecutive hospitalized patients who had been diagnosed with primary lung cancer in Second Department of Thoracic Surgery, Hunan Cancer Hospital. Formalin-fixed, paraffin-embedded specimens were cut for 10-15 sheets. Dewaxing specimens with xylene and different concentrations of ethanol according to the order processes. QIAamp DNA FFPE Tissue kit for DNA extraction. A280 / A260> 1.8 as the quality control standard of purified DNA measured by B-500 spectrophotometer. Using EGFR mutation detection kit detected EGFR exon 18, 19, 20, 21. After PCR amplification, pyrosequencing was proceeded by Pyro Mark Q24 sequencing machine. The measured sequence of EGFR gene was compared with Genbank standard sequence. Find out mutation sites and figure out the frequency of mutation sites, and then summarize result. The relationship between EGFR mutations and clinical characteristics have been analyzed with Chi-square Test. P<0.05 shows significantly statistical difference.Results: 33 occurred EGFR mutation in 100 cases(33%, 33/100). Thereinto, 19 cases showed exon 19 mutation and exon 21 mutation exist in 14 cases. We did not detect out other site mutations among them. 32 adenocarcinoma patients(47.76%, 32/67)and only 1 squamous carcinoma patient(4.17%, 1/24) occurred EGFR mutations. Rest of pathological types are detected no mutation. Male mutation rate was 16.39%(10/61), and female mutation rate of 58.97%(23/39). Mutation rate between different gender showed significantly statistical difference in ?2 Test(P = 0.000013 <0.05). Patients who have smoking history exist EGFR mutation in 9 cases(15.52%, 9/58), and mutation of non-smokers was 24(57.14%, 24/42), the mutation rate between smokers and never smoking patients were significantly different(P = 0.000015 <0.05). 22 non-smoking females lung cancer patients showed EGFR mutations(70.97%, 22/31). Mutation rates of stage I, II, III, IV was 41.30%(19/46), 26.32%(5/19), 20.83%(5/24), 57.14%(4/7), respectively. Mutation rate of well-differentiation, higher differentiation, moderate differentiation, lower differentiation and poorly differentiation was 57.14%,(4/7), 55.00%(11/20), 32.35%(11/34), 14.29%(3/21), 28.57%(4/14), respectively.Conclusion: EGFR mutation sites mainly exist in exons 19 and 21. EGFR gene mutation is related to pathological type, gender, and smoking history, but has no relationship to clinical stage. It semms like having some correlation between mutation status and degree of pathological differentiation. Revealing EGFR mutation characteristics and relationship with clinical features could help to advise potential EGFR mutation patients who would probably gain benefit form TKI.