OBJECTIVETo correlate morphological features with mutations of epidermal growth factor receptor (EGFR) in lung adenocarcinomas.

METHODSAccording to 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society International Multidisciplinary Lung Adenocarcinoma Classification, a total of 72 surgically resected lung adenocarcinomas were collected and classified into different histological subtypes and different cell types (hobnail, columnar and polygonal). EGFR gene mutation was detected with the amplification refractory mutation method provided by the EGFR mutation test kit. The correlation between these subtypes and EGFR mutations were evaluated.

RESULTSMutations of EGFR were detected in 48.6% (35/72) of lung adenocarcinomas; 19del and L858R were major mutational types (88.6%, 31/35). EGFR mutations were associated with female gender, non-smoking status, and well to moderately differentiated tumor histology. EGFR mutation types were not associated with age, smoking index, lymph node metastasis, stage, status of whether have or not have inclusion bodies or psammoma bodies and mitotic level. Correlations were observed between acinar and papillary adenocarcinoma subtypes and EGFR mutations according to the new classification. EGFR mutation was rare in the subtype of solid adenocarcinoma with mucin production and almost never observed in special subtypes (mainly mucinous and colloid adenocarcinoma). In addition, EGFR mutation was associated with the hobnail cell type.

CONCLUSIONLung adenocarcinomas of predominate acinar and papillary histological subtypes with hobnail cell morphology are good predictors for EGFR mutations.