Maintenance of genome stability after DNA damage depends on BRCA1.23 We observed that 40 weeks after DEN administration BRCA1 mRNA expression was significantly elevated in DEN-induced gp130f/f tumor tissue compared with gp130Δhepa livers, suggesting a reduced amount of DNA double-strand breaks in gp130Δhepa livers (Figure 6a). This evidence concerns the gene BRCA1 and neoplasm.