Early mortality in children with acute lymphoblastic leukemia in a developing country: the role of malnutrition at diagnosis. A multicenter cohort MIGICCL study.

The role of malnutrition at diagnosis as a predictor of early mortality in Mexican leukemia children remains controversial. The objective of present study was to investigate whether malnutrition was a predictor of early mortality during the first year of treatment in Mexican acute lymphoblastic leukemia (ALL) children through the first population-based study. A total of 794 newly diagnosed ALL pediatric patients from public hospitals of Mexico City were enrolled. A multivariate Cox proportional hazards regression model was constructed and adjusted by patient's age at diagnosis, gender, hospital of treatment, and socioeconomic status. Early mortality was high (12.1%) and malnutrition by different indicators was not associated with mortality at induction phase and at 6th month; a high risk of dying (RR = 2.08; 95% CI: 1.08-4.01) was observed in the group of malnourished children with a high-risk ALL.

Prevalence of gene rearrangements in Mexican children with acute lymphoblastic leukemia: a population study-report from the Mexican Interinstitutional Group for the identification of the causes of childhood leukemia.

Mexico has one of the highest incidences of childhood leukemia worldwide and significantly higher mortality rates for this disease compared with other countries. One possible cause is the high prevalence of gene rearrangements associated with the etiology or with a poor prognosis of childhood acute lymphoblastic leukemia (ALL). The aims of this multicenter study were to determine the prevalence of the four most common gene rearrangements [ETV6-RUNX1, TCF3-PBX1, BCR-ABL1, and MLL rearrangements] and to explore their relationship with mortality rates during the first year of treatment in ALL children from Mexico City. Patients were recruited from eight public hospitals during 2010-2012. A total of 282 bone marrow samples were obtained at each child's diagnosis for screening by conventional and multiplex reverse transcription polymerase chain reaction to determine the gene rearrangements. Gene rearrangements were detected in 50 (17.7%) patients. ETV6-RUNX1 was detected in 21 (7.4%) patients, TCF3-PBX1 in 20 (7.1%) patients, BCR-ABL1 in 5 (1.8%) patients, and MLL rearrangements in 4 (1.4%) patients. The earliest deaths occurred at months 1, 2, and 3 after diagnosis in patients with MLL, ETV6-RUNX1, and BCR-ABL1 gene rearrangements, respectively. Gene rearrangements could be related to the aggressiveness of leukemia observed in Mexican children.

Lack of evidence for human T-lymphotropic virus type 1 and mouse mammary tumor-like virus involvement in the genesis of childhood acute lymphoblastic leukemia.

BACKGROUND: In Mexico City, the incidence of childhood acute lymphoblastic leukemia (ALL) is one of the highest in the world; epidemiologic evidence suggests that infectious agents could be involved in the genesis of this disease. Early transmitted oncogenic retroviruses infecting lymphocytes are important candidates. METHODS: PCR-based assays were used to screen viral genomic sequences of human T-cell lymphotrophic virus, type 1 (HTLV1) and mouse mammary tumor virus (MMTV)-like virus (MMTV-LV) in leukemic cells from 67 pediatric patients with ALL. RESULTS: Viral genomic sequences were not detected in any sample by neither standard nor nested PCR. CONCLUSIONS: Because of the methodologic strictness and high statistical power of the study, these results suggest that HTLV1 and MMTV-LV are not involved in the genesis of childhood ALL in Mexican children. IMPACT: To our knowledge, this is the first work exploring the direct participation of HTLV1 and MMTV-LV retroviruses in childhood ALL development.