The Emerging Role of N-Acetylaspartate in Cancer.

N-Acetylaspartate (NAA), historically considered a brain-restricted neuro-metabolite, has emerged as a pivotal regulator in cancer biology. Governed by the biosynthetic enzyme N-acetyltransferase 8-like (NAT8L), the NAA axis exerts notable biological effects in malignancies. This review delineates the NAA axis as a context-dependent metabolic rheostat that is strategically hijacked by malignancies to orchestrate growth and immune evasion. Rather than a passive bystander, the NAA axis functions through distinct, histology-specific paradigms: it either serves as a metabolic reservoir to fuel lipid biomass expansion or is suppressed to redirect aspartate flux toward nucleotide biosynthesis, depending on the tumor's unique genetic and metabolic bottlenecks. Beyond cell-intrinsic reprogramming, tumor-derived NAA is increasingly linked to immune evasion by impairing cytotoxic lymphocyte function and driving pro-tumorigenic M2-like macrophage polarization. By reconciling these disparate oncogenic roles, this review highlights the NAA axis as an important node of metabolic plasticity and evaluates its potential utility as a circulating biomarker and a stratifiable therapeutic target in diverse human malignancies.