ISOC1 (isochorismatase domain-containing 1) is a cytoplasmic and peroxisomal protein with emerging roles in both cancer and immune metabolism. The precise metabolic function of ISOC1 remains incompletely characterized 1, though it contains an isochorismatase domain suggesting involvement in metabolic pathways. In cancer biology, ISOC1 exhibits context-dependent functions. It acts as an oncogene in colorectal, pancreatic, and gastric cancers, where increased expression correlates with larger tumors, advanced TNM stage, and shorter disease-free survival 123. ISOC1 knockdown suppresses cancer cell proliferation, migration, and induces apoptosis through the AKT/GSK-3β pathway in colorectal cancer 1 and promotes caspase-3/7-mediated apoptosis in pancreatic cancer 2. In gastric cancer, ISOC1 positively regulates CDK19 to drive proliferation 3. Conversely, ISOC1 functions as a tumor suppressor in hepatocellular carcinoma, where low expression associates with poor prognosis 4. In immune cells, ISOC1 supports Th1* memory T cell effector functions by regulating pyrimidine metabolism, with ISOC1 depletion impairing oxidative phosphorylation, glycolysis, and IFN-γ/IL-17 production 5. Additionally, ISOC1 plasma levels show bidirectional causal relationships with urticaria risk 6 and emerge as key nodes in sarcopenia-associated protein networks 7.