ACY1 (aminoacylase 1) encodes a homodimeric zinc-binding enzyme that catalyzes the hydrolysis of N-acetylated and N-formylated amino acids 1. The enzyme functions in protein degradation pathways, with N-acetylamino acids accumulating in urine when ACY1 is deficient 2. ACY1 is located on chromosome 3.1, a region frequently deleted in small cell lung cancer 1. The gene exhibits tumor suppressor properties, with reduced expression observed in various cancers including small cell lung cancer and colorectal cancer 13. In colorectal cancer, ACY1 expression paradoxically promotes tumor progression through ERK1 and TGF-β1 signaling pathways 3. ACY1 also plays a role in clear cell renal cell carcinoma, where it functions downstream of the MAGI2-AS3/HEY1 pathway to regulate angiogenesis 4. Clinically, ACY1 shows promise as a biomarker, with elevated plasma levels in colorectal cancer patients and reduced serum levels in schizophrenia patients and their siblings 32. The protein's ubiquitination status may serve as a prognostic marker in hepatocellular carcinoma 5.