Our analysis highlight that both Bcl‐xL mRNA and protein levels are up‐regulated in total leucocyte and in erythroblasts of PV and PMF and in hematopoietic progenitors of patients from all MPN subgroups compared to healthy donors, confirming and implementing published data.18, 19. This evidence concerns the gene BCL2L1 and myeloproliferative neoplasm.