[Epidemilogy of leukemias in children. Part 2]

The causes of most leukemias are unknown; only a few exposures have been established as risk factors. Nowadays, the AL in children is considered as the result of the interaction of different environmental factors with the genetic susceptibility to the disease. In the first part of this review, the child's environmental factors were basically covered. Now, in this second part, we are describing some factors of the child himself, as well as other proposed factors, but which have been evaluated in epidemiological research with less frequency. The most important host factor is Down's syndrome. Susceptibility aspects, such as HLA alleles, and aspects related to expositions around the home, late infections and the time in which the expositions occur, require more research. Studies that assess the interaction between the susceptibility to the acute leukemia and the environmental factors could lead to the better understanding of the causal mechanisms of the disease and to more adequate preventive strategies.