High expression of L-type amino acid transporter 1 (LAT1) predicts poor prognosis in pancreatic ductal adenocarcinomas

Background and aims Molecular target therapy against L-type amino acid transporter 1 (LAT1) is unique and expected to be developed soon. LAT1 expression was investigated in pancreatic cancer as a prognostic predictor. Methods Surgically resected pancreatic ductal adenocarcinomas (PDAC, n = 66) were investigated using immunohistochemistry. For reference, intraductal papillary mucinous carcinomas (IPMC, including intraductal papillary mucinous neoplasm (IPMN) with high-grade dysplasia or with an associated invasive carcinoma, n = 13) and adenomas (IPMA, including IPMN with low- and intermediate-grade dysplasia, n = 5) were also examined. Results LAT1 expression scores increased from PDAC to IPMA to IPMC. Kaplan-Meier analysis showed significant differences between LAT1-high and -low scores in PDAC. Even in each Ki-67-labelling index (LI) low and high PDAC group (cut off 40%), high LAT1 expression could also predict poor prognosis. Multivariable analysis showed that LAT1 expression, Ki-67 LI, tumour differentiation and size were individual prognostic factors. Conclusions LAT1 aberrant overexpression in PDAC predicts poor prognosis, independent of Ki-67 LI, and offers a potential target for future anticancer therapy with its inhibitors.