A later AAV integration study of tumors from these mice found AAV integrations in Rian, which were not clonal, as well as clonal integrations in Rtl1 (a gene in close proximity to Rian) and Tax1bp1. 49Rtl1 and Tax1bp1 are potential oncogenes, suggesting that integration into genes other than Rian could cause genotoxicity in mice, although the significance of these clonal rAAV integrations to tumor development was unclear because these integrations were found in OTC-deficient mice with a B6C3F1 hybrid background, which are known to have a high frequency of spontaneous liver tumors. This evidence concerns the gene OTC and neoplasm.