SLCO4C1 encodes an organic anion transporter predominantly expressed in kidney proximal tubular cells, where it mediates the transport of various substrates including uremic toxins, steroids, thyroid hormones, and pharmacological compounds 1. The transporter functions independently of sodium, chloride, and ATP, with activity stimulated by acidic extracellular conditions 1. SLCO4C1 plays a crucial role in renal elimination of uremic toxins such as guanidino succinate, asymmetric dimethylarginine (ADMA), and trans-aconitate, helping prevent their accumulation in chr5 kidney disease (CKD) 12. Overexpression of SLCO4C1 in rat kidney models reduced hypertension, cardiomegaly, and renal inflammation while promoting uremic toxin clearance 1. The transporter's expression is regulated by transcriptional mechanisms involving aryl hydrocarbon receptors and can be induced by statins 2. Conversely, uremic toxins like indoxyl sulfate can suppress SLCO4C1 expression through GATA3 upregulation, creating a pathological feedback loop 3. Beyond kidney function, SLCO4C1 has emerged as a hepatic cAMP transporter that inhibits lipogenesis and shows tumor suppressor activity in hepatocellular carcinoma 45. Its promoter methylation serves as a prognostic biomarker in prostate cancer 6.