The distinguishable DNA whole genome methylation profile of 2 cases of pediatric precursor B acute lymphoblastic leukaemia (BCP ALL) with prodromal, preleukemic phase: A case report.

Rationale: A prolonged, prodromal phase before definitive paediatric precursor B acute lymphoblastic leukaemia (BCP ALL) diagnosis is rarely observed. Patients concerns: In the first, the patient presented with an aplastic preleukemic phase, whilst the second presented with a rheumatic-like preliminary phase. Diagnoses: The case reports of two patients with BCP ALL with a prodromal phase lasting a few weeks are presented. Interventions and outcomes: DNAwhole genome profile methylation analysis of bonemarrowcells obtained at diagnosis revealed a pattern of methylation that was readily distinguishable from both healthy and standard course BCP ALL bone marrow samples. Lessons: The biological implication of this observation remains unclear, with many differentially methylated loci involved in many processes like neurogenesis, cell projection organization and adhesion along with leucocyte activation and apoptosis. The prevalence and clinical significance of these methylation changes is unknown but this data indicates that the epigenetic basis of BCP ALL with a prolonged, prodromal phase requires a more detailed assessment.