Relationship between LAT1 expression and response to platinum-based chemotherapy in non-small cell lung cancer patients with postoperative recurrence

Background: The aim of this study was to investigate whether L-type amino acid transporter 1 (LAT1) expression can predict poor outcome after chemotherapy in patients with non-small cell lung cancer (NSCLC). Materials and Methods: Immunohistochemistry was carried out to examine the expression of LAT1, CD98, vascular endothelial growth factor (VEGF), Ki-67, phosphorylation of Akt (p-Akt), phosphorylation of mammalian target of rapamycin (p-mTOR) and p53 in resected lung tumor specimens obtained from 56 patients treated with platinum-based chemotherapy. Results: Positive LAT1 and CD98 expression was recognized in 45% (25/56) and 34% (19/56), respectively. In NSCLC (N=56), LAT1, CD98, VEGF, Ki-67 and p53 were significant factors for predicting poor outcome, and adenocarcinoma was an independent factor for predicting favorable prognosis. LAT1 expression was closely associated with chemoresistance. In adenocarcinoma (N=37), a statistically significant inverse relationship was observed between the expression of LAT1, VEGF and Ki-67 and epidermal growth factor receptor (EGFR) mutation, and positive expression of LAT1 and VEGF was an independent factor for predicting poor prognosis after chemotherapy. Conclusion: LAT1 expression may be useful for predicting response and outcome after systemic chemotherapy.