XRCC5 and hepatocellular carcinoma: Cytogenetic analysis revealed that Ku80 heterozygosity elevated chromosomal instability in PARP−/− cells and that liver tumors isolated from these mice harbored a high degree of chromosomal aberrations, including fragments, end-to-end fusions, and recurrent nonreciprocal translocations; features reminiscent of human HCC [50].