MATERNAL LIFESTYLE AND PRENATAL RISK FACTORS FOR CHILDHOOD LEUKEMIA: A REVIEW OF THE EXISTING EVIDENCE.

Acute leukemia is the most common pediatric cancer, with an incidence peak at 2-5 years of age. Despite the medical advances improving survival rates, children suffer from significant side-effects of treatments as well as its high social and economic impact. The frequent prenatal origin of this developmental disease follows the two-hit carcinogenesis model established in the 70s: a first hit in prenatal life with the creation of genetic fusion lesions or aneuploidy in hematopoietic progenitor/stem cells, and usually a second hit in pediatric age that converts the preleukemic clone into clinical leukemia. Previous research has mostly focused on postnatal environmental factors triggering the second hit. There is scarce evidence on prenatal risk factors associated with the first hit. Mainly retrospective case-control studies suggested several environmental and lifestyle determinants as risk factors. If these associations could be confirmed, interventions focused on modifying prenatal factors might influence the subsequent risk of leukemia during childhood and reveal unexplored research avenues for the future. In this review, we aim to comprehensively summarize the currently available evidence on prenatal risk factors for the development of childhood leukemia.