Interestingly, abrogation of other components of the DDR, such as p21, Pms2 and Exo-1, can rescue survival of Terc-deficient mice without increasing cancer (Choudhury et al., 2007; Schaetzlein et al., 2007; Siegl-Cachedenier et al., 2007). The gene discussed is EXO1; the disease is cancer.