Acylcarnitines in Cancer Metabolism: Mechanistic Insights and Stratification Potential

Metabolic reprogramming constitutes a fundamental hallmark of malignancy, enabling cancer cells to sustain proliferation and survival under physiological stress. While aerobic glycolysis is well characterized, fatty acid oxidation (FAO) has emerged as a decisive driver of oncogenic progression and therapeutic resistance. Acylcarnitines (ACs), obligatory intermediates for the mitochondrial transport of long-chain fatty acids, have transcended their traditional categorization as passive metabolic byproducts to function as potent signaling entities and functional readouts of mitochondrial oxidative throughput. This review delineates the AC metabolic axis in oncology, examining the coordinated biochemical machinery, including the carnitine palmitoyltransferase (CPT) system, carnitine-acylcarnitine translocase (CACT; SLC25A20), and organic cation/carnitine transporter 2 (OCTN2), that governs cellular AC homeostasis. We further evaluate the clinical utility of altered AC profiles as non-invasive biomarkers for early diagnosis and risk stratification across diverse malignancies, highlighting their capacity to reflect metabolic bottlenecks and flux dynamics. Additionally, we scrutinize therapeutic strategies targeting the AC-FAO axis, demonstrating how the inhibition of key transporters and enzymes sensitizes tumors to conventional chemotherapy and immunotherapy. Ultimately, deciphering the systemic and spatial dynamics of ACs remains essential for advancing precision metabolic oncology and developing personalized therapeutic strategies based on metabolic profiling.