CDKN2A and cervical squamous intraepithelial neoplasia: To test the effects of irradiation doses on the risk of genomic destabilization and the associated clonal evolution of mutated cells, we analyzed the immortalization process of Arf+/− MEFs after irradiation (0.25–16 Gy at 909 mGy/min), as Arf+/− MEFs usually immortalize with CIN and the resultant loss of the Cdkn2a locus (encoding ARF) (Osawa et al., 2013).