Abstract
BACKGROUND: The correlation between L-type amino acid transporter 1 (LAT1) expression and 4-borono-2-(18) F-fluoro-phenylalanine ((18) F-FBPA) accumulation in humans remains unclear. This study aimed to investigate the correlation between LAT1 expression in tumor tissues and (18) F-FBPA accumulation in patients with head and neck cancer who participated in a clinical trial of (18) F-FBPA positron emission tomography (PET). METHODS: Altogether, 28 patients with head and neck cancer who participated in a clinical trial of (18) F-FBPA PET at our institution between March 2012 and January 2018 were included. Correlations between standardized uptake values (SUVs); the maximum SUV (SUV(max) ), the mean SUV within a 1 cm(3) sphere centered at a single point, that is, the SUV(max) (SUV(peak) ), the minimum SUV (SUV(min) ), and the intensity of LAT1 expression (maximum and minimum LAT1 expressions) were investigated. RESULTS: Weak correlations were identified between SUV(max) and LAT1 maximum score, SUV(min) and LAT1 maximum score, and SUV(min) and LAT1 minimum score (ρ = 0.427, 0.362, and 0.330, respectively). SUV(max) and LAT1 minimum score, SUV(peak) and LAT1 maximum score, and SUV(peak) and LAT1 minimum score demonstrated moderate correlations (ρ = 0.535, 0.556, and 0.661, respectively). Boron neutron capture therapy (BNCT) was performed in 2 of the 4 patients with discrepancies between (18) F-FBPA accumulation and intensity of LAT1 expression, and the intensity of LAT1 expression was a better predictor of treatment response. CONCLUSION: (18) F-FBPA accumulation and the intensity of LAT1 expression demonstrated a moderate correlation; however, LAT1 expression may be a better predictor of treatment response of BNCT in patients with discrepancies.