Specifically, it has been reported that children and adolescents with ALL and a confirmed 677C>T polymorphism of the MTHFR gene are more prone to mucositis and gastrointestinal-related adverse events, liver damage and lower platelet counts after receiving high doses of methotrexate as part of cancer treatment protocols (in ALL and non-Hodgkin lymphoma) [128,129,130,131,132,133,134,135]. The gene discussed is MTHFR; the disease is non-Hodgkin lymphoma.