Correlation between L‐amino acid transporter 1 expression and 4‐borono‐2‐(18)F‐fluoro‐phenylalanine accumulation in humans

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.