Our results show that we can clearly distinguish between two cell types based on their response to Ku70 depletion: Ku70-depletion sensitive cells, in which Ku70 depletion kills cells (such as in N-type NB cells) (Fig. 3b), and Ku70-depletion less sensitive cells (such as SHEP-1, ES2, A2780, and HEK-293T cells) (Fig. 3a), in which Ku70-depletion does not kill cells. This evidence concerns the gene XRCC6 and neuroblastoma.