EXO1 and medulloblastoma: Trubicka et al. (2017) found that pediatric medulloblastoma patients with variants in DNA repair genes (such as MSH2, RAD50, nibrin (NBN), Fanconi anemia complementation group (FANCM), and exonuclease 1 (EXO1)) experienced significantly more adverse effects from treatment containing irinotecan.