Abstract: ObjectiveTo investigate the clinical significance of the expression of laminin5 （LN5） in lung adenocarcinoma and its relationship with mutations of epidermal growth factor receptor （EGFR）. 
MethodsFrom January 2015 to December 2015， specimens from 57 cases of lung adenocarcinoma and adjacent normal tissues with pathological confirmation after surgical resection were collected. LN5 expression was detected using immunohistochemical SP methods， and EGFR mutations were assessed using liquichip technology. The expression of LN5 and its relationship with EGFR mutations were analyzed. 
ResultsThe positive expression of LN5 in adenocarcinoma tissues was 21.1％ （12／57）， higher than 1.7％ （1／57） of adjacent normal tissues （P＜0.05）. The incidence of EGFR mutations （E19+E21） was 43.9％ （25／57）， while that of wild type+E20 was 561％ （32／57）. The expression of LN-5 was associated with lymph node metastasis and EGFR mutation （P＜0.05）， but not with TNM stage （P＞0.05）. There was a negative correlation between the expression of LN-5 and EGFR mutation（r=-0.283，P＜0.05）. 
ConclusionThe expression of LN5 is upregulated in lung adenocarcinoma and is correlated with EGFR mutation status.

Key words: Lung adenocarcinoma, Laminin5（LN5）, Epidermal growth factor receptor（EGFR）