L-type amino acid transporter 1 expression is a prognostic marker in patients with surgically resected stage i non-small cell lung cancer

Aim: To evaluate the prognostic value of L-type amino acid transporter 1 (LAT1) in patients with stage I non-small cell lung cancer (NSCLC). Methods and results: A total of 282 consecutive patients with completely resected pathological stage I NSCLC were retrospectively reviewed. Expression of LAT1 and proliferative activity, as determined by the Ki67 labelling index, were also evaluated immunohistochemically and correlated with the prognosis of patients after complete resection of the tumour. LAT1 expression was positive in 114 patients (40%) [19% of adenocarcinoma (36 of 186 patients), 83% of squamous cell carcinoma (73 of 88 patients) and 63% of large cell carcinoma (five of eight patients)]. There was a significant correlation between LAT1 expression and Ki67 labelling index (γ = 0.6935, P < 0.001). LAT1 expression was significantly associated with gender, disease stage and pathological features. The 5-year survival rate of LAT1+ patients (69.1%) was significantly worse than that of LAT1- patients (89.4%; P < 0.001). Multivariate analysis confirmed that positive expression of LAT1 was an independent factor for predicting a poor prognosis. Conclusion: LAT1 expression is a promising pathological factor for predicting the prognosis in patients with resectable stage I NSCLC.