Urine as a non-invasive alternative to blood for germline and somatic mutation detection in hepatocellular carcinoma

Abstract

AbstractCell-free DNA (cfDNA) from blood has become a promising analyte for cancer genetic liquid biopsy. Urinary cfDNA has been shown to contain mutations associated with non-genitourologic cancers including hepatocellular carcinoma (HCC). In this study, we evaluate urine as a noninvasive alternative to blood-based liquid biopsy in both germline and circulating tumor DNA (ctDNA) genotyping in HCC. Using quantitative PCR (qPCR), whole-genome sequencing (WGS), and targeted NGS, DNA isolated from blood or urine of patients with HCC was analyzed for overall genome coverage, HCC hotspot coverage, and germline or somatic mutation concordance. Targeted NGS of plasma and urine cfDNA was also performed for detection of somatic variants. We found urine cfDNA, similar to plasma cfDNA, showed a major mononucleosomal species of 150-180 bp in both healthy individuals and patients with HCC. By WGS, overall genome coverage breadth was similar between urine and plasma cfDNA, with higher fraction of covered cancer-associated mutation hotspots in urine cfDNA. qPCR analyses of HCC-associated mutations (TP53, CTNNB1, and TERT) in 101 patients with HCC revealed 78% overall concordance between plasma and urine. Targeted NGS of HCC-associated gene regions in additional 15 HCC patients showed a 97% overall position-level concordance between plasma and urine cfDNA. Collectively, urine DNA can potentially be used as a completely noninvasive liquid biopsy for HCC.Significance StatementHepatocellular carcinoma (HCC) is the most common liver cancer worldwide and the fastest growing gastrointestinal cancer in the U.S. Cell-free DNA (cfDNA) which originates from various cells undergoing apoptosis or necrosis including tumor cells, is present in all body fluids levels including urine. Urinary cfDNA isolated from patients with HCC showed a similar fragment size distribution, overall genome coverage, and comparable sensitivity for detecting HCC-associated variants compared to plasma cfDNA. Urine was also determined to be a reliable source of germline genotype information, similar to peripheral blood mononuclear cells in blood-based liquid biopsies. Urine cfDNA can be used as a completely non-invasive liquid biopsy in HCC.