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

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).

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 cm³ 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.

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.

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.