〔Abstract〕 Objective To investigate the expressions and clinicopathological relationships of Trophinin associated protein( TROAP) in lung adenocarcinoma. Methods The differential expression of TROAP and its impact on patients prognosis were analyzed by exploring multiple public databases. Immunohistochemical staining was used to detect the histological score( H-Score) of TROAP in 30 patients with lung adenocarcinoma. The differences in expression and clinicopathological features( sex,age,TNM stage,Ki-67 level,smoking history,pleural effusion and Epidermal Growth Factor Receptor( EGFR) mutation status) were analyzed. Results Database analysis suggested that this gene was highly expressed in various solid tumors such as lung cancer. The survival of lung adenocarcinoma patients with high expression of TROAP gene was significantly shortened. Immunohistochemical staining suggested that the expression of this gene in tumor tissues of lung adenocarcinoma patients[H-Score( Histological Score) = 150. 00( 100. 00,180. 00) ]was significantly higher than that in adjacent normal lung tissues [H-Score= 80. 00( 58. 75,125. 00) ]. This difference had statistical significance( P = 2. 69 × 10-5). In addition,the expression of TROAP gene expression was significantly different in disease stages( P = 0. 039),whether there was distant metastasis( P = 0. 031) and different Ki-67 expressions( P = 0. 006). Conclusion TROAP may play an important role in the tumorigenesis,development,invasion and metastasis of lung adenocarcinoma. It could be used as a potential biomarker for pathogenesis,treatment and prognosis.