LAT1 expression in non-small-cell lung carcinomas: analyses by semiquantitative reverse transcription-PCR (237 cases) and immunohistochemistry (295 cases).

Abstract

OBJECTIVE:

System l-amino acid transport mediates the uptake of aromatic neutral amino acids and nutritionally essential amino acids from extracellular fluids. Little is known about the role of l-amino acid transporter 1 (LAT1), a member of the system l-amino acid transporter family, in non-small-cell lung carcinomas (NSCLCs).

PATIENTS AND METHODS:

We examined (i) LAT1 mRNA levels in 40 normal lung tissues (NLTs) and 237 NSCLCs using semiquantitative RT-PCR, (ii) LAT1 protein expression in 295 NSCLCs using immunohistochemistry, and (iii) whether LAT1 mRNA and protein expressions were related to clinicopathologic findings and outcome.

RESULTS:

The LAT1 mRNA level was significantly higher in all NSCLCs (6.81+/-1.13) than in NLT (1.00+/-0.18). The LAT1 mRNA level showed no association with clinicopathologic findings or outcome. LAT1 protein was detected with a diffuse or granular appearance within the cytoplasm and/or on the plasma membrane of tumor cells. When tumors were graded as positive if staining indicating a plasma membrane expression of LAT1 protein made up more than 10% of the tumor, the frequency of this membrane expression was found to be associated with tumor histology, differentiation grade, pathologic stage, T classification, pleural invasion, lymph-vessel invasion, and overall survival rate.

CONCLUSION:

Detection of a plasma membrane expression of LAT1 protein would appear to be of value in informing the prognosis in NSCLC cases.

• Authors: Katsuyuki Takeuchi, Sho Ogata, Kuniaki Nakanishi, Yuichi Ozeki, Sadayuki Hiroi, Susumu Tominaga, Shinsuke Aida, Hirotaka Matsuo, Tsuneaki Sakata, Toshiaki Kawai
• Journal: Lung cancer (Amsterdam, Netherlands) (Lung Cancer) Vol. 68 Issue 1 Pg. 58-65 (Apr 2010) ISSN: 1872-8332 [Electronic] Ireland
• PMID: 19559497 (Publication Type: Journal Article)
• Copyright: Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Chemical References

• Large Neutral Amino Acid-Transporter 1

Topics

• Aged
• Aged, 80 and over
• Carcinoma, Non-Small-Cell Lung (diagnosis, metabolism, pathology, physiopathology)
• Disease Progression
• Female
• Humans
• Immunohistochemistry
• Large Neutral Amino Acid-Transporter 1 (genetics, metabolism)
• Lung (metabolism, pathology)
• Lung Neoplasms (diagnosis, metabolism, pathology, physiopathology)
• Male
• Middle Aged
• Neoplasm Staging
• Prognosis
• Reverse Transcriptase Polymerase Chain Reaction