Backtracking childhood leukaemia to birth: A battle of addition.

Paediatric leukaemia has a long tail of driver mutations each of which must be 'backtracked' to samples taken at birth to identify the prenatal origin of a subtype. Presently, Bardini et al. describe the first successful backtracking of an NUTM1 rearrangement, which sheds light on the biology of this particular alteration. Continued backtracking of NUTM1 rearrangements, and all leukaemia-typical somatic alterations, is necessary to fully understand the prenatal origin of these diseases. Commentary on: Bardini et al. Prenatal origin of NUTM1 gene rearrangement in infant B-cell precursor acute lymphoblastic leukaemia. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19685.