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

Abstract

Abstract Background The correlation between L‐type amino acid transporter 1 (LAT1) expression and 4‐borono‐2‐18F‐fluoro‐phenylalanine (18F‐FBPA) accumulation in humans remains unclear. This study aimed to investigate the correlation between LAT1 expression in tumor tissues and 18F‐FBPA accumulation in patients with head and neck cancer who participated in a clinical trial of 18F‐FBPA positron emission tomography (PET). Methods Altogether, 28 patients with head and neck cancer who participated in a clinical trial of 18F‐FBPA PET at our institution between March 2012 and January 2018 were included. Correlations between standardized uptake values (SUVs); the maximum SUV (SUVmax), the mean SUV within a 1 cm3 sphere centered at a single point, that is, the SUVmax (SUVpeak), the minimum SUV (SUVmin), and the intensity of LAT1 expression (maximum and minimum LAT1 expressions) were investigated. Results Weak correlations were identified between SUVmax and LAT1 maximum score, SUVmin and LAT1 maximum score, and SUVmin and LAT1 minimum score (ρ = 0.427, 0.362, and 0.330, respectively). SUVmax and LAT1 minimum score, SUVpeak and LAT1 maximum score, and SUVpeak 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 18F‐FBPA accumulation and intensity of LAT1 expression, and the intensity of LAT1 expression was a better predictor of treatment response. Conclusion 18F‐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.

Keywords

• 4‐borono‐2‐18F‐fluoro‐phenylalanine positron emission tomography
• boron neutron capture therapy
• boronophenylalanine
• L‐type amino acid transporter 1
• neoplasm