Urine For Noninvasive Liquid Biopsy For Germline And Somatic Mutations

Circulating tumor DNA (ctDNA) from blood and peripheral blood mononuclear cells (PBMCs) are used to determine comprehensive cancer genetics and germline genomics for precision medicine. To evaluate the use of urine samples as a noninvasive alternative to blood samples, we performed a comprehensive characterization of urine DNA as an alternative to PBMC DNA for germline genomics. Whole genome sequencing (WGS) was performed in PBMC and total urine DNA in six normal subjects to compare the quality and comprehensiveness of the genomic data. There was no significant difference between the sequencing data obtained from PBMC and urine DNA upon comparing the variant calling, percent reads passing Phred score Q30 (p\u003e0.05, paired t-test), and coverage of human genome. Similar to plasma cfDNA, mononucleosomal-sized DNA was the most predominant species present in urine cfDNA. Samples from three hepatocellular carcinoma (HCC) patients were further analyzed for insert sizes by NGS, which demonstrated predominantly mononucleosomal-sized DNA fragments, with a series of peaks occurring with 10-bp periodicity, in both urine and plasma cfDNA. With shallow WGS, the genome coverage overlap was 53-61%, and by increasing the depth of coverage the overlap increased from 60% to 74%. Interestingly, 8-10% of the genome covered in plasma DNA was not detected in urine DNA, and 4-8% of the genome covered in urine DNA was not covered in plasma DNA. Next, we compared the detectability of three HCC-associated genetic mutations in the matched urine and plasma DNA obtained from 76 HCC patients including mutations at TP53 codon 249 (TP53 249T), CTNNB1 exon 3 regions 32-37 (CTNNB1 32-37), and hTERT promoter region position 124 (hTERT 124). We observed higher levels of the TP53 mutation, similar levels of CTNNB1 mutation, and lower levels of the TERT mutation in urine cfDNA compared to plasma ctDNA. This suggests a potential for urine as a potential noninvasive source for ctDNA analysis, and a combination of both urine and plasma ctDNA may increase the overall sensitivity of ctDNA detection. In conclusion, our data suggest that (1) total urine DNA can replace PBMC DNA for providing comprehensive genomic sequencing data and (2) urine can complement blood for liver cancer liquid biopsy, precision medicine, and potential applications in other cancers. Citation Format: James V. Vowles, Amy K. Kim, James P. Hamilton, Selena Y. Lin, Fwu-Shan Shieh, Harry Luu, Gabrielle Villafana, Chi-Tan Hu, Ying-Hsiu Su. Urine for noninvasive liquid biopsy for germline and somatic mutations [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 722.