The Epidemiology of Childhood Leukemia with a Focus on Birth Weight and Diet

Presence of leukemic clone-specific immunoglobulin heavy chain rearrangements in neonatal blood spots of children with B-cell precursor acute lymphoblastic leukemia

INTRODUCTION

Childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) can be traced back to birth using leukemic clone-specific immunoglobulin heavy chain (IGH) rearrangements, implying prenatal origin of this disease.

METHODS

We retrospectively analyzed neonatal blood spots (Guthrie cards) of 24 patients with childhood BCP-ALL aged 1-9.6 years (median 3.1 years) for the presence of clonotypic IGH rearrangements identified in diagnostic bone marrow samples. Based on the sequences of IGH rearrangements, 2 patient-specific primers were designed for each patient and used in semi-nested polymerase chain reaction for the detection of preleukemic clones at birth.

RESULTS

Clonotypic IGH rearrangements were detected in neonatal blood spots of 54.2% of patients (13/24). In two cases with double IGH rearrangements detected at diagnosis, only one rearrangement was present at birth, while in the third case both leukemic rearrangements were detected in neonatal blood. Guthrie card-positive findings were significantly more frequent in children ≤5 years of age than in older children (p = 0.011). Regarding patients' characteristics at birth and at diagnosis, Guthrie card-positivity was not associated with sex, birth weight and mother's age, as well as with white blood cell count, percentage of bone marrow blasts, immunophenotype and the presence of ETV6/RUNX1 and TCF3/PBX1 fusion genes at diagnosis.

CONCLUSION

Our study confirms that a large proportion of childhood BCP-ALL originates in utero, regardless of the molecular subtype defined by chromosomal aberrations. The observed trend toward younger age at diagnosis in Guthrie card-positive versus Guthrie card-negative patients implies that the age at diagnosis depends on the presence of preleukemic clone at birth, as well as on the timing of postnatal transforming genetic events.

Status of folate in healthy children in Almeria

The objective of this study is to establish reference values for folic acid in a healthy population of children aged 4-11 years and to examine related epidemiological, dietary and analytical factors. A cross-sectional study of 658 healthy children aged 4-11 years was made. Epidemiological, socioeconomic and dietary variables were analysed, the BMI Z-score was obtained, levels of serum folate and serum vitamin B₁₂ were determined and haematological, iron status and erythropoietic activity parameters were examined. The study data were analysed by non-parametric tests and linear multiple regression. The mean folate value was 8.6 ± 4.6 ng/mL (95% reference interval: 2.8-20 ng/mL). A level < 3 ng/mL (5th percentile) was considered as folate deficiency (4.6% of subjects). No child reported symptoms related to this deficiency. Folate values were significantly lower with age (p < 0.01), low NSE and low parental educational level (p: 0.0001). No relationship was found between folates and the analytical variables. According to multivariate linear regression, the variables significantly associated with serum folate were age, socioeconomic level and vitamin B₁₂.Conclusions: Serum folate levels in healthy school children are described. Age, socioeconomic level and serum vitamin B₁₂ are factors associated with folate status. Specific cut-off values for a paediatric population should be defined. What is Known: • Folic acid is an essential micronutrient for optimal growth and development; its deficit is associated with adverse health effects. • The studies on their status and deficit are not comparable due to a lack of agreement on appropriate indicators and reference values. What is New: • This study reports the levels of serum folate in a large population of healthy schoolchildren, with strict inclusion criteria in a developed country and identifies the associated sociodemographic, dietary and analytical (vitamin B12, iron parameters and erythropoietic activity) factors, avoiding potential confusion.

Role of Key Micronutrients from Nutrigenetic and Nutrigenomic Perspectives in Cancer Prevention

Regarding cancer as a genetic multi-factorial disease, a number of aspects need to be investigated and analyzed in terms of cancer's predisposition, development and prognosis. One of these multi-dimensional factors, which has gained increased attention in the oncological field due to its unelucidated role in risk assessment for cancer, is diet. Moreover, as studies advance, a clearer connection between diet and the molecular alteration of patients is becoming identifiable and quantifiable, thereby replacing the old general view associating specific phenotypical changes with the differential intake of nutrients. Respectively, there are two major fields concentrated on the interrelation between genome and diet: nutrigenetics and nutrigenomics. Nutrigenetics studies the effects of nutrition at the gene level, whereas nutrigenomics studies the effect of nutrients on genome and transcriptome patterns. By precisely evaluating the interaction between the genomic profile of patients and their nutrient intake, it is possible to envision a concept of personalized medicine encompassing nutrition and health care. The list of nutrients that could have an inhibitory effect on cancer development is quite extensive, with evidence in the scientific literature. The administration of these nutrients showed significant results in vitro and in vivo regarding cancer inhibition, although more studies regarding administration in effective doses in actual patients need to be done.

A causal mechanism for childhood acute lymphoblastic leukaemia

In this Review, I present evidence supporting a multifactorial causation of childhood acute lymphoblastic leukaemia (ALL), a major subtype of paediatric cancer. ALL evolves in two discrete steps. First, in utero initiation by fusion gene formation or hyperdiploidy generates a covert, pre-leukaemic clone. Second, in a small fraction of these cases, the postnatal acquisition of secondary genetic changes (primarily V(D)J recombination-activating protein (RAG) and activation-induced cytidine deaminase (AID)-driven copy number alterations in the case of ETS translocation variant 6 (ETV6)-runt-related transcription factor 1 (RUNX1)+ ALL) drives conversion to overt leukaemia. Epidemiological and modelling studies endorse a dual role for common infections. Microbial exposures earlier in life are protective but, in their absence, later infections trigger the critical secondary mutations. Risk is further modified by inherited genetics, chance and, probably, diet. Childhood ALL can be viewed as a paradoxical consequence of progress in modern societies, where behavioural changes have restrained early microbial exposure. This engenders an evolutionary mismatch between historical adaptations of the immune system and contemporary lifestyles. Childhood ALL may be a preventable cancer.

Effects of endoplasmic reticulum stress on autophagy and apoptosis of human leukemia cells via inhibition of the PI3K/AKT/mTOR signaling pathway

The present study aimed to explore the regulatory effects of endoplasmic reticulum stress (ERS) on the phosphoinositide 3‑kinase (PI3K)/AKT serine/threonine kinase 1 (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, and its subsequent effects on autophagy and apoptosis of human leukemia cells. Human leukemia cells were cultured and treated with various concentrations of tunicamycin for 0, 24, 48, 72 and 90 h. Subsequently, human leukemia cells were assigned into the ER activation group, which was treated with 100 ng/ml tunicamycin, the ER activation + TO901317 (PI3K inhibitor) group, and the control group. An MTT assay was conducted to detect cell proliferation. In addition, a monodansylcadaverine (MDC) assay was used to detect the formation of autophagosomes and Annexin V‑fluorescein isothiocyanate/propidium iodide double staining was used to examine cell apoptosis. Western blotting was performed to detect the expression levels of 78‑kDa glucose‑regulated protein (GRP78), phosphorylated (p)‑protein kinase R‑like endoplasmic reticulum kinase (PERK), p‑α subunit of eukaryotic initiation factor 2 (eIF2α), microtubule‑associated protein 1A/1B‑light chain 3 (LC3), caspase‑3, CCAAT‑enhancer‑binding protein homologous protein (CHOP), PI3K, AKT and mTOR. Treatment with 100 ng/ml tunicamycin for 72 h was considered the optimal condition for further experiments. Compared with in cells prior to treatment, human leukemia cells treated with tunicamycin exhibited increased expression of p‑PERK, p‑eIF2α and GRP78 after 72 h (P<0.05). In addition, the expression levels of mTOR, AKT and PI3K were decreased in the ER activation group compared with in the control and ER activation + TO901317 groups (P<0.05). Compared with in the control group, cell proliferation was inhibited and MDC fluorescence intensity was increased in the ER activation group (P<0.05). Furthermore, compared with in the control and ER activation + TO901317 groups, western blotting indicated that the expression levels of LC3‑II were increased in the ER activation group (P<0.05). The apoptotic rate was also higher in the ER activation group compared with in the control group (P<0.05), and caspase‑3 and CHOP expression was elevated in the ER activation group (P<0.05). These findings indicated that ERS may induce autophagy and apoptosis of human leukemia cells via inhibiting the PI3K/AKT/mTOR signaling pathway.

Folate deficiency as predisposing factor for childhood leukaemia: a review of the literature

BACKGROUND

Folic acid and its derivates, known as folates, are chemoprotective micronutrients of great interest because of their essential role in the maintenance of health and genomic integrity. The supplementation of folic acid during pregnancy has long been known to reduce the risk of neural tube defects (NTDs) in the foetus. Folate metabolism can be altered by many factors, including adequate intake through diet. Folate deficiency can compromise the synthesis, repair and methylation of DNA, with deleterious consequences on genomic stability and gene expression. These processes are known to be altered in chronic diseases, including cancer and cardiovascular diseases.

MAIN BODY

This review focuses on the association between folate intake and the risk of childhood leukaemia. Having compiled and analysed studies from the literature, we show the documented effects of folates on the genome and their role in cancer prevention and progression with particular emphasis on DNA methylation modifications. These changes are of crucial importance during pregnancy, as maternal diet has a profound impact on the metabolic and physiological functions of the foetus and the susceptibility to disease in later life. Folate deficiency is capable of modifying the methylation status of certain genes at birth in both animals and humans, with potential pathogenic and tumorigenic effects on the progeny. Pre-existing genetic polymorphisms can modify the metabolic network of folates and influence the risk of cancer, including childhood leukaemias. The protective effects of folic acid might be dose dependent, as excessive folic acid could have the adverse effect of nourishing certain types of tumours.

CONCLUSION

Overall, maternal folic acid supplementation before and during pregnancy seems to confer protection against the risk of childhood leukaemia in the offspring. The optimal folic acid requirements and supplementation doses need to be established, especially in conjunction with other vitamins in order to determine the most successful combinations of nutrients to maintain genomic health and wellbeing. Further research is therefore needed to uncover the role of maternal diet as a whole, as it represents a main factor capable of inducing permanent changes in the foetus.

Association of maternal and index child's diet with subsequent leukemia risk: A systematic review and meta analysis

BACKGROUND

Exploring the effect of maternal and/or childhood diet on offspring leukemogenesis is challenging, given differences in food group categories, their potentially variable impact depending on time window of exposure and the multiple leukemia subtypes. We opted to quantitatively synthesize published data on the association of maternal/child diet with leukemia risk.

METHODS

Medline was searched until June 30th, 2016 for eligible articles on the association of childhood leukemia with consumption of (i) food groups, excluding alcoholic and non-alcoholic beverages, and (ii) specific dietary supplements before/during index pregnancy and childhood.

RESULTS

Eighteen studies of case-control design (N=11,720 cases/18,721 controls) were included, of which nine assessed maternal dietary components, five index child's and four both, mainly focusing on acute lymphoblastic leukemia (ALL). Statistically significant inverse estimates for ALL were found (2 studies, 413 cases, 490 controls) for fruit (OR: 0.81, 95% CI: 0.67, 0.99); vegetables (OR: 0.51, 95% CI: 0.28, 0.94); legumes (OR: 0.76, 95% CI: 0.62, 0.94); fish (OR: 0.27, 95% CI: 0.14, 0.53, among the 0-4year old; 2 studies 215 cases, 215 controls); preconception folic acid supplementation (OR: 0.69, 95%CI: 0.50-0.95; published meta analysis plus 2 studies, 3511 cases, 6816 controls); and use of vitamins during pregnancy (OR: 0.81, 95%CI: 0.74-0.88; published meta analysis plus one study, 5967 cases, 8876 controls). The associations (2 studies) of the remaining food groups and maternal dietary supplements consumption during pregnancy as well as of childhood diet and supplements intake (2-4 studies) were non significant.

CONCLUSIONS

Maternal consumption of specific food groups comprising"healthy" items of the Mediterranean diet, preconception use of folic acid and intake of vitamins during pregnancy were associated with decreased ALL risk. Further research is needed, however preferably with homogeneous dietary information and data on immunophenotypic/cytogenetic subtypes to also explore the interaction of specific macro- and micronutrients intake with gene polymorphisms.

Opportunities During Early Life for Cancer Prevention: Highlights From a Series of Virtual Meetings With Experts

Compelling evidence suggests that early life exposures can affect lifetime cancer risk. In 2014, the Centers for Disease Control and Prevention's (CDC's) Cancer Prevention Across the Lifespan Workgroup hosted a series of virtual meetings with select experts to discuss the state of the evidence linking factors during the prenatal period and early childhood to subsequent risk of both pediatric and adult cancers. In this article, we present the results from a qualitative analysis of the meeting transcripts and summarize themes that emerged from our discussions with meeting participants. Themes included the state of the evidence linking early life factors to cancer risk, research gaps and challenges, the level of evidence needed to support taking public health action, and the challenges of communicating complex, and sometimes conflicting, scientific findings to the public. Opportunities for collaboration among public health agencies and other stakeholders were identified during these discussions. Potential next steps for the CDC and its partners included advancing and building upon epidemiology and surveillance work, developing and using evidence from multiple sources to inform decision-making, disseminating and communicating research findings in a clear and effective way, and expanding collaborations with grantees and other partners. As the science on early life factors and cancer risk continues to evolve, there are opportunities for collaboration to translate science into actionable public health practice.

Irradiation at Different Fetal Stages Results in Different Translocation Frequencies in Adult Mouse Thyroid Cells

While it is generally believed that fetuses are at high risk of developing cancers, including leukemia, after low doses of radiation, it has been reported that atomic bomb survivors exposed in utero did not show a dose response for translocations in blood T lymphocytes when they were examined at approximately 40 years of age. Subsequent mouse studies confirmed that animals irradiated during the fetal stage did not show evidence of radiation effects in lymphocytes and bone marrow cells when they were examined after reaching adulthood. However, in a study of rat mammary epithelial cells, radiation effects were clearly observed after fetal irradiation. These results indicate that the fate of chromosome aberrations induced in a fetus could vary among different tissues. Here we report on translocation frequencies in mouse thyroid cells, which were irradiated at different stages of fetal development. Cytogenetic examination was conducted using fluorescence n situ hybridization (FISH) painting of chromosomes 1 and 3. Adult mice, 2 Gy X-ray irradiated at 15.5-day-old fetuses (E15.5), showed a higher translocation frequency (30/1,155 or 25.3 × 10^-3) than nonirradiated adult controls (0/1,007 or 0.1 × 10^-3), and was near that experienced by irradiated mothers and non-pregnant adult females (43/1,244 or 33.7 × 10^-3). These results are consistent with those seen in rat mammary cells. However, when fetuses were irradiated at an earlier stage of development (E6.5) before thyroid organogenesis, the resulting observed translocation frequency was much lower (3/502 or 5.8 × 10^-3) than that in E15.5 mice. These results suggest that after fetal irradiation, tissue stem cells record radiation effects primarily when the exposure occurs in cells that have been integrated into tissue. Embryonic stem cells that have been damaged prior to integration into the niche may undergo negative selection due to apoptosis, mitotic death or stem cell-niche cell interactions. The implications of these results in interpreting cancer risks after fetal irradiation are also discussed.

Biomarkers of Nutrition for Development-Folate Review

The Biomarkers of Nutrition for Development (BOND) project is designed to provide evidence-based advice to anyone with an interest in the role of nutrition in health. Specifically, the BOND program provides state-of-the-art information and service with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect. To accomplish this objective, expert panels are recruited to evaluate the literature and to draft comprehensive reports on the current state of the art with regard to specific nutrient biology and available biomarkers for assessing nutrients in body tissues at the individual and population level. Phase I of the BOND project includes the evaluation of biomarkers for 6 nutrients: iodine, iron, zinc, folate, vitamin A, and vitamin B-12. This review represents the second in the series of reviews and covers all relevant aspects of folate biology and biomarkers. The article is organized to provide the reader with a full appreciation of folate's history as a public health issue, its biology, and an overview of available biomarkers (serum folate, RBC folate, and plasma homocysteine concentrations) and their interpretation across a range of clinical and population-based uses. The article also includes a list of priority research needs for advancing the area of folate biomarkers related to nutritional health status and development.

Perinatal risk factors for acute myeloid leukemia

Infectious etiologies have been hypothesized for acute leukemias because of their high incidence in early childhood, but have seldom been examined for acute myeloid leukemia (AML). We conducted the first large cohort study to examine perinatal factors including season of birth, a proxy for perinatal infectious exposures, and risk of AML in childhood through young adulthood. A national cohort of 3,569,333 persons without Down syndrome who were born in Sweden in 1973-2008 were followed up for AML incidence through 2010 (maximum age 38 years). There were 315 AML cases in 69.7 million person-years of follow-up. We found a sinusoidal pattern in AML risk by season of birth (P < 0.001), with peak risk among persons born in winter. Relative to persons born in summer (June-August), incidence rate ratios for AML were 1.72 (95 % CI 1.25-2.38; P = 0.001) for winter (December-February), 1.37 (95 % CI 0.99-1.90; P = 0.06) for spring (March-May), and 1.27 (95 % CI 0.90-1.80; P = 0.17) for fall (September-November). Other risk factors for AML included high fetal growth, high gestational age at birth, and low maternal education level. These findings did not vary by sex or age at diagnosis. Sex, birth order, parental age, and parental country of birth were not associated with AML. In this large cohort study, birth in winter was associated with increased risk of AML in childhood through young adulthood, possibly related to immunologic effects of early infectious exposures compared with summer birth. These findings warrant further investigation of the role of seasonally varying perinatal exposures in the etiology of AML.

Prenatal recruitment of participants for a birth cohort study including cord blood collection: results of a feasibility study in Bremen, Germany

BACKGROUND

Prospective birth cohort studies comprising follow up of children from pregnancy or birth over a long period of time, and collecting various biological samples at different times through the life-course offer a promising approach to enhance etiologic knowledge of various diseases. Especially for those where early lifetime exposures and conditions are thought to play an important role. The collection and storage of biological samples is a critical component in epidemiological studies, notably for research regarding prenatal exposures to various environmental factors as well as for DNA extraction. Our feasibility study for a birth cohort within the scope of etiology of childhood leukemia with prospective sampling of mothers and their future newborns aimed to investigate the willingness of pregnant women to participate in a birth cohort study involving collection of blood and umbilical cord blood samples. The overall aim was to develop practice-based research recommendations for a possible German birth cohort study.

METHODS

The study was conducted in Bremen, Germany, between January 2012 and March 2013. Pregnant women were eligible for recruitment if (i) their expected date of delivery was during the study recruitment phase (September 2012-February 2013), (ii) they planned to give birth at the cooperating hospital's obstetric unit and (iii) their knowledge of the German language was sufficient to understand study materials, details of participation and to fill out the prenatal self-administered questionnaire. Maternal blood and umbilical cord blood samples to be used for later research activities were collected and stored at a stem cell bank already collaborating with the hospital. 22 primary care gynecologists were invited to enroll pregnant women for the study and cooperation with one hospital was established. Expectant women were recruited during the last trimester of pregnancy, either during one of their prenatal care visits at their primary care gynecologist or later on in hospital by the attending obstetricians or project staff.

RESULTS

Of the 22 invited primary care gynecologists requested to enroll pregnant women for the study, 8 gynecologists actually collaborated. A total of 200 eligible women were invited to participate in the study, 48 (24%) of whom agreed. 34 women were enrolled by primary care gynecologists, with one gynecologist enrolling 26 women. Twelve of 14 women recruited via hospitals were enrolled by study staff. A total of 41 women consented to the collection of umbilical cord blood and maternal blood samples, and samples could be stored for 54% of them. Reason for non-participation were the uncertainty whether or not the full study would be conducted and the fact that the participants were not willing to decide for their children whether or not genetic information (cord blood) can be stored for research purposes.

CONCLUSION

Enrolling parents in a birth cohort study that includes biosampling is a challenge, but participation can be improved through close collaboration with primary care gynecologists and maternity hospitals. Cord blood collection may impede participation, especially when maternity hospitals offer an alternative option for cord blood donation.

Infant birthweight and risk of childhood cancer: international population-based case control studies of 40 000 cases

BACKGROUND

High birthweight is an established risk factor for childhood leukaemia. Its association with other childhood cancers is less clear, with studies hampered by low case numbers.

METHODS

We used two large independent datasets to explore risk associations between birthweight and all subtypes of childhood cancer. Data for 16 554 cases and 53 716 controls were obtained by linkage of birth to cancer registration records across five US states, and 23 772 cases and 33 206 controls were obtained from the UK National Registry of Childhood Tumours. US, but not UK, data were adjusted for gestational age, birth order, plurality, and maternal age and race/ethnicity.

RESULTS

Risk associations were found between birthweight and several childhood cancers, with strikingly similar results between datasets. Total cancer risk increased linearly with each 0.5 kg increase in birthweight in both the US [odds ratio 1.06 (95% confidence interval 1.04, 1.08)] and UK [1.06 (1.05, 1.08)] datasets. Risk was strongest for leukaemia [USA: 1.10 (1.06, 1.13), UK: 1.07 (1.04, 1.10)], tumours of the central nervous system [USA: 1.05 (1.01, 1.08), UK: 1.07 (1.04, 1.10)], renal tumours [USA: 1.17 (1.10, 1.24), UK: 1.12 (1.06, 1.19)] and soft tissue sarcomas [USA: 1.12 (1.05, 1.20), UK: 1.07 (1.00, 1.13)]. In contrast, increasing birthweight decreased the risk of hepatic tumours [USA: 0.77 (0.69, 0.85), UK: 0.79 (0.71, 0.89) per 0.5 kg increase]. Associations were also observed between high birthweight and risk of neuroblastoma, lymphomas, germ cell tumours and malignant melanomas. For some cancer subtypes, risk associations with birthweight were non-linear. We observed no association between birthweight and risk of retinoblastoma or bone tumours.

CONCLUSIONS

Approximately half of all childhood cancers exhibit associations with birthweight. The apparent independence from other factors indicates the importance of intrauterine growth regulation in the aetiology of these diseases.

Perinatal and familial risk factors for acute lymphoblastic leukemia in a Swedish national cohort

BACKGROUND

Perinatal factors including high birth weight have been found to be associated with acute lymphoblastic leukemia (ALL) in case-control studies. However, to the best of our knowledge, these findings have seldom been examined in large population-based cohort studies, and the specific contributions of gestational age and fetal growth remain unknown.

METHODS

The authors conducted a national cohort study of 3,569,333 individuals without Down syndrome who were born in Sweden between 1973 and 2008 and followed for the incidence of ALL through 2010 (maximum age, 38 years) to examine perinatal and familial risk factors.

RESULTS

There were 1960 ALL cases with 69.7 million person-years of follow-up. After adjusting for potential confounders, risk factors for ALL included high fetal growth (incidence rate ratio [IRR] per additional 1 standard deviation, 1.07; 95% confidence interval [95% CI], 1.02-1.11 [P =.002]; and IRR for large vs appropriate for gestational age, 1.22; 95% CI, 1.06-1.40 [P =.005]), first-degree family history of ALL (IRR, 7.41; 95% CI, 4.60-11.95 [P<.001]), male sex (IRR, 1.20; 95% CI, 1.10-1.31 [P<.001]), and parental country of birth (IRR for both parents born in Sweden vs other countries, 1.13; 95% CI, 1.00-1.27 [P =.045]). These risk factors did not appear to vary by patient age at the time of diagnosis of ALL. Gestational age at birth, season of birth, birth order, multiple birth, parental age, and parental education level were not found to be associated with ALL.

CONCLUSIONS

In this large cohort study, high fetal growth was found to be associated with an increased risk of ALL in childhood through young adulthood, independent of gestational age at birth, suggesting that growth factor pathways may play an important long-term role in the etiology of ALL.

[Minor phenotypic variants in patients with acute lymphoblastic leukemia from west Mexico]

INTRODUCTION

Acute lymphoblastic leukemia (ALL) has been associated with an excess of minor phenotypic variants (MPV), including common variants and minor anomalies, indicative of an altered phenogenesis. The objective of the study was to determine the association between MPV and ALL.

PATIENTS AND METHODS

In a hospital based case-control study, we studied 120 children with ALL (including standard and high risk) and 120 healthy children as a control group, matched for age and sex, seen in the Hospital Civil de Guadalajara Dr. Juan I. Menchaca (Guadalajara, Mexico). In both groups, 28 anthropometric measurements were made, as well as a systematic search for 405 MPV, through a physical examination. Adjusted odds ratio was estimated (aOR) with its intervening variables by logistic regression. The confidence interval was 95% (95%CI).

RESULTS

Anthropometric signs associated with ALL were: long upper segment (aOR= 2.19, 95%CI: 1.01-4.76), broad jaw (aOR= 2.62, 95%CI: 1.29-5.30), narrow ears (aOR= 6.22, 95%CI: 2.60-14.85), and increase in internipple distance (aOR= 2.53, 95%CI: 1.07-5.98). The hypoplasia mesofacial, broad forehead, small nose, short columella, narrow ears, telethelia, Sydney crease (SC), Greek type feet and café-au-lait spots (CALS), had a 3 to 17 times higher frequency in children with ALL. By number, an association was found from ≥4 MPV (aOR= 2.14, 95%CI: 1.25-3.66, P=.004).

CONCLUSIONS

From ≥4 MPV, an association was found with ALL, suggesting prenatal factors in phenogenesis and leukemogenesis. CALS and SC were confirmed as MPV in children with ALL.

Frequent and sex-biased deletion of SLX4IP by illegitimate V(D)J-mediated recombination in childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) accounts for ∼25% of pediatric malignancies. Of interest, the incidence of ALL is observed ∼20% higher in males relative to females. The mechanism behind the phenomenon of sex-specific differences is presently not understood. Employing genome-wide genetic aberration screening in 19 ALL samples, one of the most recurrent lesions identified was monoallelic deletion of the 5' region of SLX4IP. We characterized this deletion by conventional molecular genetic techniques and analyzed its interrelationships with biological and clinical characteristics using specimens and data from 993 pediatric patients enrolled into trial AIEOP-BFM ALL 2000. Deletion of SLX4IP was detected in ∼30% of patients. Breakpoints within SLX4IP were defined to recurrent positions and revealed junctions with typical characteristics of illegitimate V(D)J-mediated recombination. In initial and validation analyses, SLX4IP deletions were significantly associated with male gender and ETV6/RUNX1-rearranged ALL (both overall P < 0.0001). For mechanistic validation, a second recurrent deletion affecting TAL1 and caused by the same molecular mechanism was analyzed in 1149 T-cell ALL patients. Validating a differential role by sex of illegitimate V(D)J-mediated recombination at the TAL1 locus, 128 out of 1149 T-cell ALL samples bore a deletion and males were significantly more often affected (P = 0.002). The repeatedly detected association of SLX4IP deletion with male sex and the extension of the sex bias to deletion of the TAL1 locus suggest that differential illegitimate V(D)J-mediated recombination events at specific loci may contribute to the consistent observation of higher incidence rates of childhood ALL in boys compared with girls.

MLL-SEPT5 fusion transcript in infant acute myeloid leukemia with t(11;22)(q23;q11)

Chromosomal rearrangements involving the MLL gene at band 11q23 are the most common genetic alteration encountered in infant acute myeloid leukemia. Reciprocal translocation represents the most frequent form of MLL rearrangement. Currently, more than 60 partner genes have been identified. We report here a case of de novo acute myeloid leukemia with a t(11;22)(q23;q11) in a 23-month-old child. Fluorescence in situ hybridization study revealed that the 3'MLL segment was translocated onto the derivative chromosome 22 and the breakpoint on chromosome 22 was located in or near the SEPT5 gene at 22q11.21. Long distance inverse-polymerase chain reaction was used to identify precisely the MLL partner gene and confirmed the MLL-SEPT5 fusion transcript. Involvement of the SEPT5 gene in MLL rearrangement occurs very rarely. Clinical, cytogenetic and molecular features of acute myeloid leukemia with a MLL-SEPT5 fusion gene are reviewed.

The Childhood Leukemia International Consortium

BACKGROUND

Acute leukemia is the most common cancer in children under 15 years of age; 80% are acute lymphoblastic leukemia (ALL) and 17% are acute myeloid leukemia (AML). Childhood leukemia shows further diversity based on cytogenetic and molecular characteristics, which may relate to distinct etiologies. Case-control studies conducted worldwide, particularly of ALL, have collected a wealth of data on potential risk factors and in some studies, biospecimens. There is growing evidence for the role of infectious/immunologic factors, fetal growth, and several environmental factors in the etiology of childhood ALL. The risk of childhood leukemia, like other complex diseases, is likely to be influenced both by independent and interactive effects of genes and environmental exposures. While some studies have analyzed the role of genetic variants, few have been sufficiently powered to investigate gene-environment interactions.

OBJECTIVES

The Childhood Leukemia International Consortium (CLIC) was established in 2007 to promote investigations of rarer exposures, gene-environment interactions and subtype-specific associations through the pooling of data from independent studies.

METHODS

By September 2012, CLIC included 22 studies (recruitment period: 1962-present) from 12 countries, totaling approximately 31000 cases and 50000 controls. Of these, 19 case-control studies have collected detailed epidemiologic data, and DNA samples have been collected from children and child-parent trios in 15 and 13 of these studies, respectively. Two registry-based studies and one study comprising hospital records routinely obtained at birth and/or diagnosis have limited interview data or biospecimens.

CONCLUSIONS

CLIC provides a unique opportunity to fill gaps in knowledge about the role of environmental and genetic risk factors, critical windows of exposure, the effects of gene-environment interactions and associations among specific leukemia subtypes in different ethnic groups.

Increased incidence of childhood, prostate and breast cancers in relatives of childhood cancer patients

Whether cancer predisposing familial factors are associated with childhood tumors is unclear. The purpose was to study the incidence of childhood and adult tumors in extended families of children with cancer. Family history of cancer was obtained through questionnaires, and the Swedish Population-, and Cancer Registries for 194 childhood cancer patients aged ≤18 years, diagnosed 1972-2009. Standardized cancer incidence ratios (SIR), and 95% confidence intervals (CI) were estimated and compared with expected rates. Overall, 21 of the 194 patients had any relative with a childhood tumor. When restricted to first- to third degree relatives, increased incidences of childhood (SIR: 2.5; 95% CI: 1.3-4.4) and adult tumors (SIR: 1.5; 95% CI: 1.3-1.7), especially in the prostate (SIR: 2.7; 95% CI: 1.9-3.8) and breast (SIR: 1.7; 95% CI: 1.2-2.4) were observed. Prostate and breast cancers were observed at earlier than average ages. No TP53 mutations or known cancer predisposing syndromes were found in families with multiple childhood tumors. Familial factors may increase the risk for childhood cancer and modify the age of onset of common adult tumors. Studying extended families with multiple childhood tumors may be a valuable approach to understanding the etiology of childhood tumors.

Antenatal maternal bereavement and childhood cancer in the offspring: a population-based cohort study in 6 million children

Background:

Prenatal stress may increase the susceptibility to childhood cancer by affecting immune responses and hormonal balance. We examined whether antenatal stress following maternal bereavement increased the risk of childhood cancer.

Methods:

All children born in Denmark from 1968 to 2007 (N=2 743 560) and in Sweden from 1973 to 2006 (N=3 400 212) were included in this study. We compared cancer risks in children born to women who lost a first-degree relative (a child, spouse, a parent, or a sibling) the year before pregnancy or during pregnancy with cancer risks in children of women who did not experience such bereavement.

Results:

A total of 9795 childhood cancer cases were observed during follow-up of 68 360 707 person years. Children born to women who lost a child or a spouse, but not those who lost other relatives, had an average 30% increased risk of any cancer (hazard ratio (HR) 1.30, 95% confidence interval (CI) 0.96–1.77). The HRs were the highest for non-Hodgkin disease (512 cases in total, HR 3.40, 95% CI 1.51–7.65), hepatic cancer (125 cases in total, HR 5.51, 95% CI 1.34–22.64), and testicular cancer (86 cases in total, HR 8.52, 95% CI 2.03–37.73).

Conclusion:

Our data suggest that severe antenatal stress following maternal bereavement, especially due to loss of a child or a spouse, is associated with an increased risk of certain childhood cancers in the offspring, such as hepatic cancer and non-Hodgkin disease, but not with childhood cancer in general.

Quercetin-induced apoptosis of HL-60 cells by reducing PI3K/Akt

To explore the effect and mechanism of quercetin on proliferation and apoptosis of leukemia cells, and provide a theoretical basis for its clinical application. HL-60 leukemia cell lines was treated with different dose quercetin, the proliferation activity of leukemia cells was assessed by MTT method; the morphological changes of apoptosis of HL-60 cells, including nuclear condensation and DNA fragmentation, were observed by Hoechst 33258 fluorescence staining, the apoptosis rate and caspase 2,3 activation were assessed by flow cytometry, and the cell signal pathway including phosphatidylinositol 3-kinase (PI3K), phosphorylated protein kinase B (pAkt), Bcl-2, Bax were detected by western blotting. Quercetin could significantly decrease the proliferation activity of HL-60 cells through the blockade of G(0)/G(1) phase, and induce the apoptosis of HL-60 cells in a time- and dose-dependent manner. Quercetin caused leukemia cells apoptosis by decreasing the protein expression of PI3K and Bax, the inhibitory phosphorylation of Akt, the decreased levels of Bcl-2 protein and increased activations of caspase-2 and -3, and increased poly(ADP-ribose) polymerase cleavage. Our results indicate that the apoptotic processes caused by quercetin are mediated by the decrease of pAkt and Bcl-2 levels, the increase of Bax level, and the activation of caspase families in HL-60 cells.

Immunophenotype and cytogenetic characteristics in the relationship between birth weight and childhood leukemia

BACKGROUND

High birth weight increases the risk of childhood acute lymphoid leukemia (ALL) through unknown mechanisms. Whether this risk is specific to ALL subtypes is unknown, and low case numbers have prevented investigation of the rarer leukemias. Here we address these associations using a large population-based dataset.

PROCEDURE

Using the National Registry of Childhood Tumors, birth weights of 7,826 leukemia cases, defined by immunophenotype and cytogenetic subgroup, were compared with those of 10,785 controls born in England and Wales between 1980 and 2007.

RESULTS

The risk for overall leukemia increases 7% with each 0.5 kg increase in birth weight (OR 1.07, 95%CI 1.04-1.10). This risk is limited to the lymphoid leukemias (OR 1.08, 95%CI 1.05-1.12) diagnosed between 1 and 9 years of age. Analysis by cytogenetic feature reveals that there appears to be association with specific chromosomal abnormality: the risk of tumors with high hyperdiploid karyotypes increases 12% per 0.5 kg increase in birth weight (OR 1.12, 95%CI 1.05-1.20), and t(1;19) tumors show an increased risk of 41% per 0.5 kg increase (OR 1.41, 95%CI 1.09-1.84). The risk of acute myeloid leukemia is elevated in high and low birth weight babies. There is no significant risk relationship to other leukemias or myeloproliferative diseases.

CONCLUSIONS

Birth weight is a risk factor for ALL and AML. Other subtypes of the disease are not significantly affected. There appears to be association with specific chromosomal abnormality, which may aid our understanding of the development of childhood leukemia in utero.

The 5-minute Apgar score as a predictor of childhood cancer: a population-based cohort study in five million children

OBJECTIVE

The aetiology of childhood cancer remains largely unknown but recent research indicates that uterine environment plays an important role. We aimed to examine the association between the Apgar score at 5 min after birth and the risk of childhood cancer.

DESIGN

Nationwide population-based cohort study.

SETTING

Nationwide register data in Denmark and Sweden.

STUDY POPULATION

All live-born singletons born in Denmark from 1978 to 2006 (N=1 771 615) and in Sweden from 1973 to 2006 (N=3 319 573). Children were followed up from birth to 14 years of age.

MAIN OUTCOME MEASURES

Rates and HRs for all childhood cancers and for specific childhood cancers.

RESULTS

A total of 8087 children received a cancer diagnosis (1.6 per 1000). Compared to children with a 5-min Apgar score of 9-10, children with a score of 0-5 had a 46% higher risk of cancer (adjusted HR 1.46, 95% CI 1.15 to 1.89). The potential effect of low Apgar score on overall cancer risk was mostly confined to children diagnosed before 6 months of age. Children with an Apgar score of 0-5 had higher risks for several specific childhood cancers including Wilms' tumour (HR 4.33, 95% CI 2.42 to 7.73).

CONCLUSIONS

A low 5 min Apgar score was associated with a higher risk of childhood cancers diagnosed shortly after birth. Our data suggest that environmental factors operating before or during delivery may play a role on the development of several specific childhood cancers.

Physical activity and pediatric cancer survivorship

Owing to improved treatment pro-tocols in the last 25 years there have been dramatic improvements in the 5-year relative survival rate of the most prevalent childhood cancers. For instance, the 5-year relative survival rate among children for all cancer sites combined, improved from 58% to 80% in patients diagnosed in 1975-1977 and in 1996-2004 respectively. However, as survival rates have improved, there has been an increasing recognition of adverse short and longer term effects associated with treatment and cancer itself, which we describe in detail in this chapter. There is growing interest in those interventions that can counteract the adverse effects of treatment and cancer. Because such adverse effects are further aggravated by physical inactivity, a special emphasis is being placed on physical activity (PA) interventions. Results are promising: there is increasing evidence that regular PA can improve the overall health status, functional capacity, and quality of life (QOL) of children with cancer as well as of older survivors of childhood cancer.

Birth weight and order as risk factors for childhood central nervous system tumors

OBJECTIVE

To determine whether birth characteristics related to maternal-fetal health in utero are associated with the development of childhood central nervous system tumors.

STUDY DESIGN

We identified, from the California Cancer Registry, 3733 children under age 15 diagnosed with childhood central nervous system tumors between 1988 and 2006 and linked these cases to their California birth certificates. Four controls per case, matched on birth date and sex, were randomly selected from the same birth files. We evaluated associations of multiple childhood CNS tumor subtypes with birth weight and birth order.

RESULTS

Low birth weight was associated with a reduced risk of low-grade gliomas (OR=0.67; 95% CI, 0.46 to 0.97) and high birth weight was associated with increased risk of high-grade gliomas (OR=1.57; 95% CI, 1.16 to 2.12). High birth order (fourth or higher) was associated with decreased risk of low-grade gliomas (OR=0.75; 95% CI, 0.56 to 0.99) and increased risk of high-grade gliomas (OR=1.32; 95% CI, 1.01 to 1.72 for second order).

CONCLUSIONS

Factors that drive growth in utero may increase the risk of low-grade gliomas. There may be a similar relationship in high-grade gliomas, although other factors, such as early infection, may modify this association. Additional investigation is warranted to validate and further define these findings.

Polymorphisms in innate immunity genes and risk of childhood leukemia

The immune system plays an important role in the control of cancer development. To investigate possible genetic contribution to childhood leukemia risk in the innate immune system, we performed an association study for the 1214 SNPs in 146 gene regions related to innate immunity using GoldenGate (Illumina) oligonucleotide pool assay (OPA) in 106 case patients and 123 controls. Childhood leukemia risk was estimated as odds ratios and 95% confidence intervals adjusted for age, gender and birth weight. The minP test was used to identify statistically significant association at gene level. Three SNPs (STAT6 rs703817, C1qG rs17433222, and MBP rs3794845) were significantly associated with childhood leukemia risk (p(trend) < 0.001, minP < 0.01). The most significant association with childhood leukemia risk was for STAT6 rs703817 (GA vs GG: 0.48 (0.26-0.87), AA vs GG: 0.21 (0.07-0.61), p(trend) = 0.0003, minP = 0.002). Subgroup analysis showed that Ly96 rs78380171 and MBP rs3794845 were significantly associated with the risk of acute lymphoblastic leukemia (p(trend) < 0.001). Our results suggest that genetic polymorphisms in innate immunity genes might play a role in the genesis of childhood leukemia with limited biologic evidence. Additional, larger studies are needed to identify the mechanism of these genes in childhood leukemia patients.

Exercise in adult and pediatric hematological cancer survivors: an intervention review

Observational research has shown that the physical activity levels of survivors of hematological cancer are low, with deleterious health consequences. This review summarizes the research on exercise interventions in adult and pediatric hematological cancer survivors. We searched MEDLINE, SPORTDiscus, CINAHL, Embase, Cochrane and PEDro through September 2009 for exercise intervention studies in children and adults with any type of hematological cancer. In the 24 adult intervention studies reviewed, we found strong evidence (that is, > or =3 high-quality studies and > or =75% reporting a significant benefit) for a benefit on body composition. Weak, but promising, evidence (> or =3 high-quality studies, but <75% reporting a significant benefit) was found for cardiorespiratory fitness, fatigue, muscle strength, physical functioning and quality of life. In pediatric interventions (13 studies), we found strong evidence for a benefit on muscle strength and cardiorespiratory fitness, particularly, if training was conducted in the hospital setting. Evidence is weak for ankle dorsiflexion, physical functioning and body composition. No exercise-related risks were identified in adults or children studies. Though more randomized controlled trials are needed, a growing body of literature supports the notion that regular physical activity is safe and has potential benefits for both adult and pediatric hematological cancer survivors.

A review of the potential association between childhood leukemia and benzene

Chronic exposure to high concentrations of benzene is an established cause of acute myeloid leukemia (AML) in occupationally exposed workers. Based on this association, it is not unreasonable to assume that children could also get AML if they were exposed to comparable levels of benzene. Fortunately, reports of such exposures and subsequent AML development in children are non-existent. However, the question of whether children can develop leukemia at far lower, environmental levels of benzene remains. The existing scientific evidence relevant to this question will be addressed in this review. While positive findings have been reported, the collective literature does not indicate that exposure to environmental levels of benzene is related to an increased risk of childhood leukemia. Our understanding of this important issue would be strengthened by additional studies that accurately characterize exposures as well as differentiate between the various forms of leukemias observed in children.

Dietary factors and the risk for acute infant leukemia: evaluating the effects of cocoa-derived flavanols on DNA topoisomerase activity

There is cumulative strong evidence that diets rich in flavanols can provide certain positive health benefits, particularly with respect to the cardiovascular system. Consequently, it has been suggested that increasing one's dietary intake of flavanols may be of benefit. Complicating this idea, there are reports that high intakes of certain flavonoids during pregnancy are associated with an increased risk for acute infant leukemia due to a poison effect of select polyphenolic compounds on DNA topoisomerase (topo) II activity that promotes aberrant chromosomal translocations. In the current study, we characterized the effects of select flavanols (epicatechin and catechin monomers), and select flavanol dimers and longer oligomers, on topo II activity, and on cellular toxicity in vitro. In contrast to the chemotherapeutic drug etoposide (VP16) and the flavonol quercetin, which strongly inhibited topo II activity and increased the formation of cleavage complexes demonstrating a poison effect, the flavanols epicatechin and catechin had little effect on topo II enzyme activity. Accordingly, several fold greater concentrations of the flavanols were required to achieve cellular toxicity similar to that of quercetin and VP16 in cultures of myeloid and lymphoid cells. Low cellular toxicity and limited topo II inhibition were also observed with a procyanidin-rich cocoa extract. Of all the flavanols tested, the dimers (B2, B5 and a mix of both) exerted the greatest inhibition of topo II and inhibited cellular proliferation rates at concentrations similar to quercetin. However, in contrast to quercetin, the dimers did not function as topo II poisons. Collectively, our in vitro data show that cocoa-derived flavanols have limited effects on topo II activity and cellular proliferation in cancer cell lines. We predict that these compounds are likely to have limited leukemogenic potential at physiological concentrations.

Birth weight, sex and childhood cancer: A report from the United Kingdom Childhood Cancer Study

Birth weight has been linked to the risk of developing childhood cancer, in particular childhood leukaemia. However, despite many childhood cancers having a male predominance and boys generally weighing more than girls at birth few studies have reported sex-specific associations. The relationship between birth weight and childhood cancer risk was examined using information from a national case-control study. Children (0-14 years) newly diagnosed with cancer in GB were ascertained between 1991 and 1996 (n=3651) and for comparison, controls matched on sex, month and year of birth were identified from primary care population registers (n=6337). Birth weights were obtained from the Office of National Statistics for all targeted subjects born in England and Wales. Overall, cases were, on average, 30 g heavier at birth than controls (p=0.003) with differences seen by cancer type; those diagnosed with hepatic tumours weighing around 500 g less than controls at birth (p<0.0001) and those with leukaemia being, on average, 50 g heavier than those without (p=0.001). An interaction between birth weight and sex was found for acute leukaemia (chi(2)=11.2, p=0.04) and when data were stratified by sex, an association between high birth weight and risk of ALL was seen with girls (>4000 g, OR 1.86, 95% CI 1.38-2.50, chi(2) for trend 20.2, p<0.0001). Our results support the hypothesis that birth weight is an important determinant for childhood cancer. In addition, the data are consistent with the notion that childhood leukaemia has a prenatal origin.

Genetic susceptibility to childhood leukaemia

The aetiology of leukaemias among children is believed to be distinct from that of adults, mainly due to the clearer role for early life exposures, including those in utero. However, few risk factors have been established, because of the challenge of studying a disease with relatively low incidence. Identified risk factors, including ionizing radiation, chemotherapeutic agents and specific genetic abnormalities, explain < 10% of incidence. Although the causes for the remaining 90% are unknown, it is possible that genetic susceptibility factors, either alone or in conjunction with environmental factors, may be involved. In this paper, the authors (a) review the evidence surrounding genetic susceptibility factors, with emphasis on the genes' main effects; (b) review some recent developments in the Northern California Childhood Leukaemia Study (NCCLS) as a case study of design and practical considerations in genetic epidemiology research and (c) highlight both challenges and future directions in this exciting research area.

Infant feeding and the incidence of endometrial cancer

Biological mechanisms could support both an inverse and a direct association between exposure to breast milk in infancy and the risk of cancer. Having been breast-fed has been investigated in relation to the risk of breast and other cancer sites, and conflicting results have been reported. The association between infant feeding and the risk of endometrial cancer has not been explored. From 1976 to 2004, we followed 74,757 cancer-free participants in the Nurses' Health Study who had not undergone hysterectomy. Information on infant feeding was self-reported by study participants. A total of 708 incident cases of endometrial cancer were diagnosed during follow-up. After adjusting for age, family history of endometrial cancer, birth weight, premature birth, and birth order, the incidence of endometrial cancer was not associated with ever having been breast-fed (hazards ratio, 0.94; 95% confidence interval, 0.79-1.11) or duration of having been breast-fed [hazards ratio (95% confidence interval): 1.11 (0.80-1.54), 0.84 (0.62-1.13), 1.02 (0.79-1.31), respectively, for < or =3, 4-8, and > or =9 months of having been breastfed; P for trend = 0.88]. There was no significant effect modification by menopausal status, anthropometric factors (somatotype at age 5 or 10 years, body mass index at age 18 years, or current body mass index), or by other early-life exposures (birth weight, premature birth or exposure to parental smoking in childhood). Additional adjustment for adulthood risk factors of endometrial cancer did not materially change the results. Having been breast-fed was not associated with the incidence of endometrial cancer in this cohort, but statistical power for analyses restricted to premenopausal women was limited.

Parental and infant characteristics and childhood leukemia in Minnesota

BACKGROUND

Leukemia is the most common childhood cancer. With the exception of Down syndrome, prenatal radiation exposure, and higher birth weight, particularly for acute lymphoid leukemia (ALL), few risk factors have been firmly established. Translocations present in neonatal blood spots and the young age peak of diagnosis suggest that early-life factors are involved in childhood leukemia etiology.

METHODS

We investigated the association between birth characteristics and childhood leukemia through linkage of the Minnesota birth and cancer registries using a case-cohort study design. Cases included 560 children with ALL and 87 with acute myeloid leukemia (AML) diagnoses from 28 days to 14 years. The comparison group was comprised of 8,750 individuals selected through random sampling of the birth cohort from 1976-2004. Cox proportional hazards regression specific for case-cohort studies was used to compute hazard ratios (HR) and 95% confidence intervals (CIs).

RESULTS

Male sex (HR = 1.41, 95% CI 1.16-1.70), white race (HR = 2.32, 95% CI 1.13-4.76), and maternal birth interval > or = 3 years (HR = 1.31, 95% CI 1.01-1.70) increased ALL risk, while maternal age increased AML risk (HR = 1.21/5 year age increase, 95% CI 1.0-1.47). Higher birth weights (>3798 grams) (HRALL = 1.46, 1.08-1.98; HRAML = 1.97, 95% CI 1.07-3.65), and one minute Apgar scores < or = 7 (HRALL = 1.30, 95% CI 1.05-1.61; HRAML = 1.62, 95% CI 1.01-2.60) increased risk for both types of leukemia. Sex was not a significant modifier of the association between ALL and other covariates, with the exception of maternal education.

CONCLUSION

We confirmed known risk factors for ALL: male sex, high birth weight, and white race. We have also provided data that supports an increased risk for AML following higher birth weights, and demonstrated an association with low Apgar scores.