CBR3 (carbonyl reductase 3) is an NADPH-dependent oxidoreductase enzyme that catalyzes the reduction of carbonyl compounds to their corresponding alcohols 1. The enzyme exhibits activity toward ortho-quinones and non-quinone substrates including isatin and the anticancer drug oracin, with 1,2-naphthoquinone identified as its optimal substrate 2. CBR3 likely functions in protection against cytotoxicity of exogenous quinones and plays a role in xenobiotic metabolism 23. In cancer biology, CBR3 variants influence doxorubicin pharmacokinetics and toxicity; the common CBR3 11G>A polymorphism associates with reduced doxorubicinol formation, lower CBR3 expression in breast tissue, and greater chemotherapy response with increased myelosuppression 4. CBR3 expression is upregulated in hepatocellular carcinoma development 5, and knockout of CBR3 increases susceptibility of cardiomyocytes to doxorubicin-induced cardiotoxicity, implicating it as a cardioprotective factor 6. Notably, CBR3-AS1 (an antisense lncRNA) rather than the protein itself associates with poor cancer prognosis across multiple malignancies through distinct molecular mechanisms involving redox regulation and DNA repair 789.