BMC Cancer 2005, 5:33 http://www.biomedcentral.com/1471-2407/5/33 Table 4: Comparison of the proportion of promyelocytic leukemias for Mexican children with Hispanic children from other countries and cities. Adults Children Leukemia type Promyelocytic leukemia LAC-USC (37) 37.5% LA County and AML study (37) 24.3% Peru (38) Puebla, Mexico (39) California* (3) Puebla, Mexico (39) Mexico City, IMSS Range in non- Hispanic populations** (37) 22.0% 20.0% 8.3% 30.0% 21.0% 3–13% LAC-USC = Los Angeles County-University of Southern California; LA: Los Angeles; AML = acute myeloid leukemia; IMSS = Instituto Mexicano del Seguro Social. * This is a population-based study in which a frequency of 3.8%was found for non-Hispanic children. ** This range is based on proportions found in series of cases. (References) which 36% of the cases with cancer were Hispanic chil- dren, it was found that the use of "Propargite", a pesticide used primarily in orchards and vineyards to control mites, was related to the higher rates of childhood leukemia [36]. Honduras, Guatemala, Costa Rica, and Nicaragua to keep records of cancer in children, which will be highly reliable and which, therefore, can provide valid and timely data on the great concern that child cancer represents in the Latin American countries. The standardized incidence rate of ALL for children under 12 years of age in El Salvador was found to be less than the AAIR reported for Costa Rica or for Florida, where the highest percentage of Hispanics are of Caribbean and Central American origin, but this rate is relatively higher than that reported by SEER for all races [30]. This compar- ison has to be taken with some reservation because the AAIRs of SEER are reported for children under 15 years of age, whereas that of El Salvador is for only those under 12 years of age. The frequency of AML M3 in the Hispanic population has been reported to be higher than those for other popula- tions [37]. This has been observed both for children and for adults [3,37-39] (Table 4). In the present study, it was found that, in Mexico City, the frequency was 21%, a value consistent with the data that the frequency of AML M3 is higher in a population of Hispanic origin. The present study has the advantage over other studies that were carried out in Latin America because it is population- based. One study has proposed that the elevated fre- quency of AML in the Hispanic population may be related not only genetic factors but also nutritional ones [38]. It is important to emphasize that, despite recent data pub- lished on the incidence of leukemias in Latin America [5,40] or in Hispanics from the USA [29], those study periods were prior to those analyzed here. Finally, it can be stated that the rates here presented are similar to those reported for Latin America, thereby supporting the relia- bility of these results. This is the start of a project that intends to join efforts in Mexico City, El Salvador, Conclusion The AAIRs reported for Mexico City and the rate in chil- dren from 0–11 years old in El Salvador were similar to those that have been reported by other Latin American countries. The AAIR of ALL in Mexico City is one of the highest in the world. Competing interests The author(s) declare that they have no competing interests. Authors' contributions JMMA conceived and designed the study, analyzed the data and wrote the first draft of the manuscript. MB and AFG designed the study, analyzed the data, and provided guidance to all aspects of this project. RL, SJO, GR, MLPS, GGM, RBR, AOF, MOA and MCMG registered, recorded, and analyzed the data. All authors read and approved the final manuscript. Acknowledgements This work was partially financed by the Instituto Mexicano del Seguro Social, through its Strategic and International Exchange Projects (Proyectos Estratégicos y de Intercambio Internacional) programs (FP-00038/218/415/ 459; FP-2002/089 and FP-2003/162), by the Consejo Nacional de Ciencia y Tecnología (CONACyT Fondos Sectoriales SALUD-2003-C01-102) and by the Fundación Ayúdame a Vivir pro Niños con Cáncer of El Salvador. We thank Veronica Yakoleff and Yolanda Castelazo for editing the manuscript. Page 7 of 9 (page number not for citation purposes)