Familial history of cancer and leukemia in children younger than 2 years of age in Brazil

Identifying childhood leukemia with an excess of hematological malignancies in first-degree relatives in Brazil

Background

Familial aggregation in childhood leukemia is associated with epidemiological and genomic factors. Albeit epidemiological studies on the familial history of hematological malignancies (FHHMs) are scarce, genome-wide studies have identified inherited gene variants associated with leukemia risk. We revisited a dataset of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) patients to explore the familial aggregation of malignancies among their relatives.

Methods

A series of 5,878 childhood leukemia (≤21 years of age) from the EMiLI study (2000-2019) were assessed. Lack of well-documented familial history of cancer (FHC) and 670 cases associated with genetic phenotypic syndromes were excluded. Leukemia subtypes were established according to World Health Organization recommendations. Logistic regression-derived odds ratios (ORs) and 95% confidence intervals (CIs) were performed and adjusted by age as a continuous variable, where ALL was the reference group for AML and conversely. The pedigree of 18 families with excess hematological malignancy was constructed.

Results

FHC was identified in 472 of 3,618 eligible cases (13%). Ninety-six of the 472 patients (20.3%) had an occurrence of FHHMs among relatives. Overall, FHC was significantly associated with AML (OR, 1.36; 95% CI, 1.01-1.82; p = 0.040). Regarding the first-degree relatives, the OR, 2.92 95% CI,1.57-5.42 and the adjOR, 1.16 (1.03-1.30; p0.001) were found for FHC and FHHM, respectively.

Conclusion

Our findings confirmed that AML subtypes presented a significant association with hematological malignancies in first-degree relatives. Genomic studies are needed to identify germline mutations that significantly increase the risk of developing myeloid malignancies in Brazil.

Maternal prenatal exposure to environmental factors and risk of childhood acute lymphocytic leukemia: A hospital-based case-control study in China

OBJECTIVE

To investigate an association between maternal prenatal exposure to several environmental factors and risk of childhood acute lymphocytic leukemia (ALL), and the possible interactions in the Chinese population.

METHODS

345 cases with ALL and their 1:1 age, gender, residence region matched controls aged 0-15 years were recruited from four hospitals in Henan Province from 2014 to 2016. Information was collected by interviews using a questionnaire. Unconditional logistic regression adjusted for age, gender, residence region and relevant confounders was carried out to generate the odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Our data indicate that maternal prenatal exposure to interior housing renovation (adjusted OR: 2.98, 95% CI: 1.51-5.86) or pesticides (adjusted OR: 1.48, 95% CI: 1.67-2.28) increased the risk of childhood ALL. Various subgroup analyses stratified by child's gender, age at diagnosis and other factors also supported these results. However, no interaction was detected between exposure to internal housing renovation and pesticides using an additive model. No significant links between maternal exposures to, environmental tobacco smoking (ETS), antipyretic analgesia intake, or viral infectious diseases with risk of ALL were detected.

CONCLUSION

Findings in our study are in line with the existing literatures, which support the hypothesis that maternal prenatal exposure to interior housing renovation and pesticides are risk factors for childhood ALL. Notably, we found no interaction between these two risk factors, these findings may inform prevention and early detection strategies.

Concordant B-cell precursor acute lymphoblastic leukemia in non-twinned siblings

Associating the risk of childhood acute lymphoblastic leukemia (ALL) with genetic predisposition is still a challenge. Here, we discuss two non-twinned sibs (girl and boy) diagnosed with B-cell precursor (BCP-ALL) and ETV6-RUNX1. BCP-ALL clinical onset occurred 10months apart from each diagnosis. One child is alive in complete continuous remission, whereas, the other relapsed and evolved to death with resistance to ALL treatment. Despite the fact that BCP-ALL with ETV6-RUNX1 usually results in a very good prognosis, the sibs experienced divergent outcomes; a remarkable difference in one child that presented a more aggressive disease was higher leukocytosis associated with IKZF1 deletion. The familial history of cancer and genetic susceptibility was explored. The sibs were absolutely identical in all 17 loci of genes tested; GSTM1, GSTT1, NQO1, TP53, and TP63 were wild-type, whereas at least one copy of the variant allele for IKZF1, ARID5B, PTPRJ and CEBPE was present. The familial pattern of ETV6 was tested by the 12p microsatellite analysis and demonstrated that deletions occurred in one child but not the other, while heterozygous patterns were found in the parents. Altogether, our data suggest that genetic predisposition aligned with chance haa an additive effect in BCP-ALL outcome.

Excess congenital non-synonymous variation in leukemia-associated genes in MLL- infant leukemia: a Children's Oncology Group report

Infant leukemia (IL) is a rare sporadic cancer with a grim prognosis. Although most cases are accompanied by MLL rearrangements and harbor very few somatic mutations, less is known about the genetics of the cases without MLL translocations. We performed the largest exome-sequencing study to date on matched non-cancer DNA from pairs of mothers and IL patients to characterize congenital variation that may contribute to early leukemogenesis. Using the COSMIC database to define acute leukemia-associated candidate genes, we find a significant enrichment of rare, potentially functional congenital variation in IL patients compared with randomly selected genes within the same patients and unaffected pediatric controls. IL acute myeloid leukemia (AML) patients had more overall variation than IL acute lymphocytic leukemia (ALL) patients, but less of that variation was inherited from mothers. Of our candidate genes, we found that MLL3 was a compound heterozygote in every infant who developed AML and 50% of infants who developed ALL. These data suggest a model by which known genetic mechanisms for leukemogenesis could be disrupted without an abundance of somatic mutation or chromosomal rearrangements. This model would be consistent with existing models for the establishment of leukemia clones in utero and the high rate of IL concordance in monozygotic twins.