ATM and thymus neoplasm: Thus, Tdp2−/−Atm−/− mice showed a median survival of 140 days, contrasting with 307 days for the Atm−/− single mutant (Fig. 2a), and the probability of developing a thymic tumour during the 1st year of life increased from a 43% in Atm−/− to a 72% in the Tdp2−/−Atm−/− double mutant (Fig. 2b).