Importantly, the high expression levels of TRKB, BDNF, or both were observed in 100% (19/19), 73.7% (14/19), and 73.7% (14/19) of MD/PD-OSCC, respectively, contrasting with the 24.0% (6/25), 16.0% (4/25), and 8.0% (2/25) detected in WD-OSCC (P < 0.001). This evidence concerns the gene NTRK2 and Wilson disease.