Consistent with prior knowledge that incorporation of cystatin C adds precision to the eGFR equation in patients with malnutrition, sarcopenia, and cirrhosis,12,44,45 we found that hypoalbuminemia and anemia had an important role in detecting an eGFRcys that was more than 30% lower than the eGFRcr in patients with cancer. This evidence concerns the gene CST3 and cancer.