A different effect of the level of p16^INK4A expression on OS in young versus old AML patients. (A) Kaplan-Meier analysis depicted for AML samples with higher p16^INK4A mRNA expression levels versus AML samples with lower p16^INK4A mRNA expression levels within the youngest one-third of patients of the cohort of 525 AMLs (n = 175). No effect of the level of expression of p16^INK4A mRNA on OS could be observed (P = .57). (B) Kaplan-Meier analysis depicted for AML samples with high p16^INK4A mRNA expression levels versus AML samples with lower p16^INK4A mRNA expression levels within the oldest one-third of patients of the cohort of 525 AMLs (n = 175). Patients with high p16^INK4A mRNA expression levels (ie, fourth quartile) showed a significantly better OS compared with patients with lower p16^INK4A mRNA expression levels (ie, first, second, and third quartiles) in this cohort of 175 oldest AML patients (P = .04).