Urine as an Alternative to Blood for Cancer Liquid Biopsy and Precision Medicine

Abstract

Blood liquid biopsy is a powerful tool to provide cancer genetics via detection of biomarkers like circulating tumor DNA (ctDNA) to reduce cancer death through precision medicine and has shown potential in the early detection of cancer. However, urine analysis of ctDNA, a completely noninvasive and possibly more practical procedure for cancer screening, has not been thoroughly explored. Using hepatocellular carcinoma (HCC) as a model, we examined if urine can be an alternative to blood for liquid biopsy. Our study indicated that quantification of TP53 and CTNNB1 genes by qPCR assays in matched plasma and urine samples showed that the plasma samples generally had more DNA but both were detected in significant quantities. Employing a panel of HCC biomarkers including genetic mutations at TP53 codon 249 [G:C to T:A transversion (TP53 249T)], CTNNB1 exon 3 regions 32-37 (CTNNB1 32-37), and hTERT promoter region position 124 (hTERT 124) and aberrant methylation of RASSF1A mRASSF1A), detection of these modifications in urine and plasma from HCC patients were confirmed. We observed that ctDNA marker detection was independent of detection using serum AFP, the most used biomarker for liver cancer screening. Thus, the sensitivity of screening was improved when combining ctDNA markers with AFP as shown in the receiver operating characteristic curve (ROC) analysis for performance of ctDNA markers for distinguishing HCC from non-HCC (cirrhosis and hepatitis), with an area under the ROC (AUROC) increase from 0.799 to 0.904 and 20% more liver cancer detected as compared to AFP alone. In conclusion, our data suggests that urine can complement blood for liver cancer liquid biopsy and precision medicine with potential applications to other cancers as well.