ATM and retinoblastoma: Interestingly, as described elsewhere, cells from cancer syndromes show either a maximal number of MRE11 foci from 10 min to 1 h after 2 Gy X-rays (e.g., retinoblastoma, tuberous sclerosis complex, and neurofibromatosis type 1) or the MRE11 foci are impaired (e.g., in BRCA1-, BRCA2-, BLM-, FANC-, and ATM-mutated cells) [33,43].