Nonhomologous end-joining protein Ku70 is similar at interstitial and subtelomeric DSBs. Repair proteins RAD51, BRCA1 and CtIP are greatly increased at subtelomeric DSBs. ATM is reduced at subtelomeric DSBs compared to interstitial DSBs. ATR is increased at subtelomeric DSBs compared to interstitial DSBs. DSBs near telomeres are more likely to be inappropriately processed.