To examine the impact of serum albumin we reviewed 325 HDMTX 5 g/m2 courses in a cohort of 51 children treated on the NOPHO ALL 2008 protocol, dividing the courses into four groups with different levels of baseline albumin (A < 25 g/L, B 25–29 g/L, C 30–34 g/L and D ≥ 35 g/L). The gene discussed is ALB; the disease is acute lymphoblastic leukemia.