In this cohort of paediatric patients, one patient with common ALL exhibited strongly increased relative leukaemic blast cell numbers together with a lack of increased PLA2R1 promoter methylation in both BM and PB samples at diagnosis, suggesting that PLA2R1 promoter hypermethylation is a frequent (95%, 19 out of 20 B-cell ALL patients), but not indispensable event during childhood leukaemogenesis. The gene discussed is PLA2R1; the disease is acute lymphoblastic leukemia.