Biological significance of fluorine-18-α-methyltyrosine (FAMT) uptake on PET in patients with oesophageal cancer.

Purpose:18F-FAMT as an amino-acid tracer for positron emission tomography (PET) is useful for detecting human neoplasms. 18F-FAMT is accumulated in tumour cells solely via L-type amino-acid transporter 1 (LAT1). This study was conducted to investigate the biological significance of 18F-FAMT uptake in patients with oesophageal cancer.Methods:From April 2008 to December 2011, 42 patients with oesophageal cancer underwent both 18F-FAMT PET/CT and 18F-FDG PET/CT before surgical treatment. The immunohistochemical analysis of LAT1, CD98, Ki-67, CD34, p53, p-Akt and p-mTOR was performed on the primary lesions. In vitro experiments were performed to examine the mechanism of 18F-FAMT uptake.Results:High uptake of 18F-FAMT was significantly associated with advanced stage, lymph node metastasis and the expression of LAT1, CD98, Ki-67 and CD34. LAT1 expression yielded a statistically significant correlation with CD98 expression, cell proliferation, angiogenesis and glucose metabolism. In vitro experiments revealed that 18F-FAMT was specifically transported by LAT1.Conclusions:The uptake of 18F-FAMT within tumour cells is determined by the LAT1 expression and correlated with cell proliferation and angiogenesis in oesophageal cancer. The present experiments also confirmed the presence of LAT1 as an underlying mechanism of 18F-FAMT accumulation. [ABSTRACT FROM AUTHOR]