However, bone marrow transfer was not performed in these animals due to anticipated off-target effects on transgenic tumor growth during irradiation27,28 Compared with control groups (KRasLA2 and KRasLA2 + ganciclovir mice), ganciclovir-treated HSV-TK/Col1 + KRasLA2 mice showed significantly fewer lung tumors at 5 months of age, as assessed either by visual inspection or by histological analysis (Supplementary Fig. 3A). The gene discussed is TKT; the disease is neoplasm.