Interestingly, ARG1 activity evaluated at pH 7.1 positively correlated with tumor grade, increasing from a median activity of 29.6 mg/h of urea in HD to 85.4 mg/h in GII, 93.9 and 152.8 mg/h in GIII and GIV, arguing for ARG1 activity as a potential marker of glioma progression from grade III to GIV, although longitudinal studies are required to confirm and strengthen this conclusion. This evidence concerns the gene ARG1 and central nervous system cancer.