Pediatric Hematopathology in the era of advanced molecular diagnostics: what we know and how we can apply the updated classifications

Pediatric hematologic malignancies often show genetic features distinct from their adult counterparts, which reflects the differences in their pathogenesis. Advances in the molecular diagnostics including the wide use of next-generation sequencing (NGS) technology have revolutionized the diagnostic workup for hematologic disorders and led to the identification of new disease subgroups as well as prognostic information that impacts the clinical treatment. The increasing recognition of the importance of germline predisposition in various hematologic malignancies also shapes the disease models and management. Although germline predisposition variants can occur in patients with myelodysplastic syndrome/neoplasm (MDS) of all ages, the frequency is highest in the pediatric patient population. Therefore, evaluation for germline predisposition in the pediatric group can have significant clinical impact. This review discusses the recent advances in juvenile myelomonocytic leukemia (JMML), pediatric acute myeloid leukemia (AML), B-lymphoblastic leukemia/lymphoma (B-ALL) and pediatric MDS. This review also includes a brief discussion of the updated classifications from the International Consensus Classification (ICC) and the 5th edition World Health Organization (WHO) classification regarding these disease entities.