The effects of PACSIN2 polymorphism on the incidence of severe mucositis during consolidation therapy for pediatric ALL were confirmed in another cohort of patients, considering 67 cases developing the adverse event during therapy according to the protocol AIEOP-BFM ALL 2000, which involves four weekly infusion of methotrexate at the dose of 2 g/m2 and concomitant daily treatment with mercaptopurine at the dose of 25 mg/kg. Here, PACSIN2 is linked to acute lymphoblastic leukemia.