Landscape of Somatic and Age-Related Pathogenic Structural Variations in Hepatocellular Carcinoma Revealed by Long-Read Sequencing.

Hepatocellular carcinoma (HCC) was characterized by a highly complex genome, with structural variations (SVs) playing a significant role in its development. In this study, we employed Oxford Nanopore Technology long-read sequencing in paired tumor and adjacent normal liver tissues from 74 Chinese HCC patients to thoroughly characterize the landscape of somatic SVs. Our analysis revealed that somatic SVs were more prevalent in hepatitis B virus (HBV)-related HCC, with chromosome 1 emerging as a major hotspot, and several members of the chromosome 1 open reading frame (C1orf) family genes expression level exhibited significant age-related difference. Notably, HBV-related HCC cases exhibited a higher frequency of deletions, particularly among younger ones (≤ 35 years old). In addition, we observed an increased burden of HBV integration events in younger ones. Remarkably, the divergent-paired related homeobox (DPRX) loci was identified as a novel gene for HBV integration in younger patients. Together, these findings delineated the somatic SV landscape in HCC and underscored age-associated HBV-related genomic alterations as key pathological features of hepatocarcinogenesis.