Whole genome sequencing data for 10 hepatocellular carcinomas (HCC) and matched non-tumor liver tissues + optical mapping data for 4 HCC and 3 matched non-tumor liver tissues.

Oncogene activation leads to replication stress and promotes genomic instability. Here we combine optical mapping and whole genome sequencing to explore in-depth the nature of structural variants (SVs) induced by replication stress in cyclin-activated hepatocellular carcinomas (CCN-HCC). In addition to classical tandem duplications, CCN-HCC display frequent intra- and inter-chromosomal templated insertion cycles (TIC) likely resulting from template switching events. Template switching preferentially involves active topologically associated domains that are close in the 3D genome organization. Template sizes depend on the type of cyclin activation and are coordinated within each TIC. Replication stress induces continuous accumulation of SVs during CCN-HCC progression, fostering the acquisition of new driver alterations and large-scale copy-number changes at TIC borders. Together, this analysis sheds light on the mechanisms, dynamics and consequences of SV accumulation in tumors with oncogene-induced replication stress.EGA study EGAS00001005629