BCR and myelofibrosis: In children and adolescents myelofibrosis (MF) is the rarest type of BCR::ABL1-neg MPNs [2, 6, 7], and so far there was no study analysing the outcomes of allo-HCT in a larger group of paediatric patients with MF, and therefore the data on allo-HCT outcomes in them remain casuistic and scant [11–14].