Relationship between EGFR Mutations and Pathological Classification and ？Specimen of Lung Adenocarcinoma

Background and objective With the development of genetic mutations and targeted drugs, accurate therapy of lung adenocarcinoma attracts much more attention, and more research is focued on epidermal growth factor receptor (EGFR). It is unclear whether the result of EGFR mutation and pathology type is consistent with different specimens. In our study, by comparing the relationship between EGFR mutations and pathological classification of lung adenocarcinoma in surgical resection of specimen and biopsy specimen, to discuss the relationship between EGFR mutations and pathological classification of and the influence of specimen type on EGFR gene detection. Methods A total of 163 cases of surgical resection of sample of lung adenocarcinoma (pulmonary resection and pulmonary lobectomy) and 173 cases of biopsy specimen [mucosa biopsy, needle biopsy of lung, and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA)] were performed by gene sequencing method and amplification refractory mutation system (ARMS) and the majority of the type was confirmed (lepidic, acinar, papillary, micropapillary, solid) according to the classification of lung adenocarcinoma in 2015 World Health Organization (WHO). The statistics was used in surgical and biopsy sample respectively. Results The gene mutation of EGFR in surgical and biopsy sample of lung adenocarcinoma was 62.58% (102/163) and 65.9% (114/173) respectively, and no significant difference was found (P>0.05). The mutation of EGFR in female was predominant both of the two groups (P<0.05). The mutation rate of EGFR over the age of 60 was significantly lower than that below 60 in surgical specimen, while it was not related to age in biopsy sample. The constituent ratio of pathology type was different in the two groups (χ2=8.04, P<0.05). Among 102 cases of lung adenocarcinoma in surgical specimen, the acinar took up the highest proportion (54.9%), followed by the lepidic (23.53%) and the papillary (17.65%). The solid adenocarcinoma accounted for the minimal percentage (3.9%). The mutation of 19 and 21 exon alone was most common. The mutation rate of 21 exon in the lepidic was higher than that in the acinar and papillary (P<0.05), but the mutation rate of 19 exon in the papillary was higher than that in the lepidic (P<0.05). There was no significant difference of 19 and 21 exon in the acinar and papillary. Among 114 cases of lung adenocarcinoma in the biopsy specimen, the most percentage was the acinar (48.25%), the lepidic was secondly, and the papillary, micropapillary and solid