Indeed, functional germline mutations of some cancer-related genes have been found in familial ALL (e.g., PAX5 and ETV6) (Shah et al., 2013; Noetzli et al., 2015) or enriched in sporadic cases (e.g., ETV6 and CDKN2A) (Moriyama et al., 2015; Xu et al., 2015), accounting for a small proportion of ALL patients. Here, CDKN2A is linked to acute lymphoblastic leukemia.