What is the deadliest cancer type amongst children?

See below. All can be deadly, but a.L.L is the most common in young children.
DIPG. The overall cure rate for acute lymphoblastic leukemia (all) is great at ~ 90%. Medulloblastoma is also improving at ~75%. On the other end of the spectrum is diffuse intrinsic pontine glioma (dipg), a tumor located in the pons (middle) of the brain stem. The 2 year survival rate is only 10%, with practically no survivors at 5 years (the usual metric used for cure).
Hard to tell. Medulloblastoma is a deadly neuro cancer that is frequently seen in children. The survival rate has steadily increased over the recent years. Leukemias, of which acute lymphocytic leukemia (all) are common. Again, the survival rate (5 years) has gotten better with the advent of modern chemotherapy.