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.