PTEN and acute lymphoblastic leukemia: In general, PTEN abnormalities in pediatric patients are associated with non-significantly worse outcome,12, 13, 23 although in adult patients, the impact was significantly adverse.14 However, whereas one study of pediatric patients found that a trend for adverse impact was not seen in the presence of a NOTCH1 mutation,13 the study of adult patients reported that presence of a PTEN or RAS abnormality ablated the benefit of a NOTCH1 mutation.14RAS mutations had no impact on clinical outcome in a study of pediatric ALL, but no data were given for the different subgroups.26