Platelet dense granule secretion defects may obscure α-granule secretion mechanisms: evidence from Munc13-4-deficient platelets.

would have been missed. Further, ethnic differences in incidence trends have only been observed in childhoodALLand are not present in other childhood cancers (eg, childhood brain tumors), suggesting that changes in ethnic classification are unlikely to be solely responsible for trend differences. In utero exposure to factors such as tobacco are likely to have remained stable or decreased in prevalence during this period. Other suspected risk factors for childhood leukemia that may explain the increase in incidence in Hispanic children, such as childhood atopic conditions, pesticide exposure, and maternal and child weight, have increased during this period, but may not be specific to Hispanic children and require further evaluation. Large, well-designed epidemiologic studies of childhood leukemiawithdiverse ethnic backgrounds, such as theCaliforniaChildhood Leukemia Study, seek to further elucidate the reasons for the observed increases in incidence rates among Hispanic children in the last 2 decades.