Childhood solid tumours in relation to infections in the community in Cumbria during pregnancy and around the time of birth

Exposure to nitrosatable drugs during pregnancy and childhood cancer: A matched case-control study in Denmark, 1996-2016

BACKGROUND

Nitrosatable drugs can be synthesized to N-nitroso compounds in human stomach. In a pregnant woman, N-nitroso compounds can be translocated to the fetus through the placenta. Maternal exposure of nitrosatable compounds during pregnancy has been associated with childhood brain tumors and leukemia. However, few studies have investigated an association between nitrosatable drug exposure during pregnancy and childhood cancer. We examined if maternal prescriptions of nitrosatable drugs received during pregnancy are associated with childhood cancer.

METHODS

A matched case-control study was conducted using Danish nationwide registry data from 1995 to 2016. Each childhood cancer case was matched with twenty-five controls. Maternal exposure of nitrosatable drugs during pregnancy was identified from the Danish National Prescription Register. A multivariable conditional logistic regression model was used to estimate adjusted odds ratios (adj.OR) with 95% confidence intervals (CI) for each childhood cancer type.

RESULTS

Maternal prescriptions of nitrosatable drugs positively associate with central nervous system tumors (adj.OR = 1.25; 95% CI = 1.04-1.51) and neuroblastoma (adj.OR = 1.96; 95% CI = 1.34-2.85) in offspring. We also observed a positive association between perinatal exposure of nitrosatable drugs and acute lymphoblastic leukemia (adj.OR = 1.31; 95% CI = 1.07-1.59), however, it appeared to be due to confounding by indication, i.e., maternal infections.

CONCLUSION

Nitrosatable drug use during pregnancy potentially increased risk of central nervous system tumors and neuroblastoma. While a positive association between maternal prescriptions of nitrosatable drugs and acute lymphoblastic leukemia should be interpreted cautiously because of confounding by indication.

Spatial analysis of the glioblastoma proteome reveals specific molecular signatures and markers of survival

Molecular heterogeneity is a key feature of glioblastoma that impedes patient stratification and leads to large discrepancies in mean patient survival. Here, we analyze a cohort of 96 glioblastoma patients with survival ranging from a few months to over 4 years. 46 tumors are analyzed by mass spectrometry-based spatially-resolved proteomics guided by mass spectrometry imaging. Integration of protein expression and clinical information highlights three molecular groups associated with immune, neurogenesis, and tumorigenesis signatures with high intra-tumoral heterogeneity. Furthermore, a set of proteins originating from reference and alternative ORFs is found to be statistically significant based on patient survival times. Among these proteins, a 5-protein signature is associated with survival. The expression of these 5 proteins is validated by immunofluorescence on an additional cohort of 50 patients. Overall, our work characterizes distinct molecular regions within glioblastoma tissues based on protein expression, which may help guide glioblastoma prognosis and improve current glioblastoma classification.

Occupational livestock or animal dust exposure and offspring cancer risk in Denmark, 1968-2016

OBJECTIVE

To examine associations with occupational livestock or other animal dust exposure and offspring cancer risk.

METHODS

In this population-based case-control study of Danish children aged < 17 years old, 5078 childhood cancer cases diagnosed 1968-2016 were matched to cancer-free controls by birth year and sex (n = 123,228). Occupational livestock or animal dust exposure was identified using a job-exposure matrix. We employed multivariable conditional logistic regression models to estimate associations with offspring cancer for births 1968-2016 and 1989-2016, with the latter timeframe reflecting a period of presumed higher exposure due to changes in Danish farming practices. Sensitivity analyses considered place of birth (urban areas vs. rural areas and small towns).

RESULTS

For births 1968-2016, paternal exposure from offspring birth to cancer diagnosis was associated with central nervous system tumors (adjusted odds ratio [OR] = 1.30, 95% confidence interval [CI] 1.04-1.63) and germ cell tumors (OR = 1.82, 95% CI 1.05-3.27), while maternal pregnancy exposure was associated with astrocytoma (OR = 1.89, 95% CI 1.00-3.57). For births 1989-2016, paternal exposure from offspring birth to cancer diagnosis was negatively associated with acute lymphoid leukemia (OR = 0.58, 95% CI 0.33-1.00). For births in rural areas only, maternal exposure from offspring birth to cancer diagnosis was positively associated with acute myeloid leukemia (OR = 2.16, 95% CI 1.09-4.29).

CONCLUSIONS

This study suggests that paternal occupational animal exposure is associated with offspring germ cell tumors, and maternal pregnancy exposure with astrocytomas. Our results are mixed with respect to leukemia subtypes.

Relevance of the Measles Virus Expression in Cancer - an Update

Evidence of an association between classical Hodgkin lymphoma and the measles virus has previously been presented by our group. Arguments held against our thesis were reevaluated. Substantiation of a relationship between the measles virus and additional solid tumors was submitted. Moreover, a pathogenic pathway was suggested to support a possible contribution of the measles virus to the development of classical Hodgkin lymphoma. We have chosen to exclude a discussion of measles virotherapy, since this carries distinct implications. We now add new evidence regarding the expression of the measles virus phosphoprotein in a few cancers. We also suggest a role in this context for atypical measles syndrome in malignant tumors. Last, we propose a collaboration which may make the best, on the one hand of our cohort of classical Hodgkin lymphoma, half of which carry the measles virus expression in their tumor cells. The planned study will also look into the patients vaccination records and into a previous history of the measles disease. On the other hand, cohorts of patients diagnosed with late onset measles will be assessed for the eventual diagnosis of atypical measles syndrome and will be followed up for the subsequent development of a malignant tumor.

Childhood brain tumor epidemiology: a brain tumor epidemiology consortium review

Childhood brain tumors are the most common pediatric solid tumor and include several histologic subtypes. Although progress has been made in improving survival rates for some subtypes, understanding of risk factors for childhood brain tumors remains limited to a few genetic syndromes and ionizing radiation to the head and neck. In this report, we review descriptive and analytical epidemiology childhood brain tumor studies from the past decade and highlight priority areas for future epidemiology investigations and methodological work that is needed to advance our understanding of childhood brain tumor causes. Specifically, we summarize the results of a review of studies published since 2004 that have analyzed incidence and survival in different international regions and that have examined potential genetic, immune system, developmental and birth characteristics, and environmental risk factors. Cancer Epidemiol Biomarkers Prev; 23(12); 2716-36. ©2014 AACR.

Exposure to infections and risk of leukemia in young children

BACKGROUND

Epidemiologic studies indicate that infections in early childhood may protect against pediatric acute lymphoblastic leukemia (ALL).

METHODS

We identified 3,402 ALL cases among children 0 to 5 years of age using the California Cancer Registry. From California birth records we randomly selected controls in a 20:1 ratio and frequency matched them to cases by birth year. We investigated markers of exposure to infections, including month of birth, timing of birth in relation to influenza and respiratory syncytial virus (RSV) seasons, and birth order based on data from California birth certificates and national infection surveillance systems.

RESULTS

We observed an increased risk of ALL for spring and summer births, and for those first exposed to an influenza or RSV season at nine to twelve months of age compared with those exposed during the first three months of life, and this association was stronger among first born children [odds ratios (OR), 1.44 and 95% confidence intervals (CI), 1.13-1.82, for influenza exposure at nine to twelve months of age]. Decreased risk was observed with increasing birth order among non-Hispanic whites but not Hispanics (OR, 0.76 and 95% CI, 0.59-096, for fourth or higher birth order among whites).

CONCLUSION

Our results support the hypothesis that infections in early childhood decrease risk of ALL.

IMPACT

Our findings implicate early life exposure to infections as protective factors for ALL in young children.

Does the measles virus contribute to carcinogenesis? - a review

An association between the measles virus and classical Hodgkin lymphoma has previously been suggested by us. This has been refuted by two European groups. A reevaluation of the arguments held against our thesis was carried out and further evidence for a relationship between the measles virus and additional solid tumors has been presented. We have suggested a molecular mechanism to support a possible contribution of the virus to carcinogenesis in classical Hodgkin lymphoma.

Patterns of exposure to infectious diseases and social contacts in early life and risk of brain tumours in children and adolescents: an International Case-Control Study (CEFALO)

Background:

Infectious diseases and social contacts in early life have been proposed to modulate brain tumour risk during late childhood and adolescence.

Methods:

CEFALO is an interview-based case–control study in Denmark, Norway, Sweden and Switzerland, including children and adolescents aged 7–19 years with primary intracranial brain tumours diagnosed between 2004 and 2008 and matched population controls.

Results:

The study included 352 cases (participation rate: 83%) and 646 controls (71%). There was no association with various measures of social contacts: daycare attendance, number of childhours at daycare, attending baby groups, birth order or living with other children.

Cases of glioma and embryonal tumours had more frequent sick days with infections in the first 6 years of life compared with controls. In 7–19 year olds with 4+ monthly sick day, the respective odds ratios were 2.93 (95% confidence interval: 1.57–5.50) and 4.21 (95% confidence interval: 1.24–14.30).

Interpretation:

There was little support for the hypothesis that social contacts influence childhood and adolescent brain tumour risk. The association between reported sick days due to infections and risk of glioma and embryonal tumour may reflect involvement of immune functions, recall bias or inverse causality and deserve further attention.

Birth weight and other perinatal factors and childhood CNS tumors: a case-control study in California

AIMS

We conducted a large registry-based study in California to investigate the association of perinatal factors and childhood CNS tumors, with analysis by tumor subtype.

METHODS

We linked California cancer and birth registries to obtain information on 3308 cases and 3308 controls matched on age and sex. We examined the association of birth weight, gestational age, birth order, parental ages, maternal conditions during pregnancy, newborn abnormalities and the risk of childhood CNS tumors using conditional logistic regression, with adjustment for potential confounders.

RESULTS

The odds ratio (OR) per 1000 g increase in birth weight was 1.11 (95% CI: 0.99-1.24) for total childhood CNS tumors, 1.17 (95% CI: 0.97-1.42) for astrocytoma and 1.28 (95% CI: 0.90-1.83) for medulloblastoma. Compared to average-for-gestational age, large-for-gestational age infants were at increased risk of glioma (OR=1.86, 95% CI: 0.99-3.48), while small-for-gestational age infants were at increased risk of ependimoma (OR=2.64, 95% CI: 1.10-6.30). Increased risk of childhood CNS tumors was observed for 5-year increase in maternal and paternal ages (OR=1.06, 95% CI: 1.00-1.12 and 1.05, 95% CI: 1.00-1.10 respectively). Increased risk of astrocytoma was detected for 5-year increase in paternal age (OR=1.08; 95% CI: 1.00-1.16) and increased risk of glioma for maternal age ≥ 35 years old (OR=1.87; 95% CI: 1.00-3.52). Maternal genital herpes during pregnancy was associated with a pronounced increase in risk of total CNS tumors (OR=2.74; 95% CI: 1.16-6.51). Other (non-sexually transmitted) infections during pregnancy were associated with decreased risk of total CNS tumors (OR=0.28, 95% CI: 0.09-0.85). Maternal blood/immune disorders during pregnancy were linked to increased risk of CNS tumors (OR=2.28, 95% CI: 1.08-4.83) and medulloblastoma (OR=7.13, 95% CI: 0.82-61.03). Newborn CNS abnormalities were also associated with high risk of childhood CNS tumors (OR=4.08, 95% CI: 1.13-14.76).

CONCLUSIONS

Our results suggest that maternal genital herpes, blood and immunological disorders during pregnancy and newborn CNS abnormalities were associated with increased risk of CNS tumors. Maternal infections during pregnancy were associated with decreased risk of CNS tumors. Advanced maternal and paternal ages may be associated with a slightly increased risk of CNS tumors. Factors associated with CNS tumor subtypes varied by subtype, an indicator of different etiology for different subtypes.

Space-time clustering of childhood central nervous system tumours in Yorkshire, UK

BACKGROUND

We specifically tested the aetiological hypothesis that a factor influencing geographical or temporal heterogeneity of childhood central nervous system (CNS) tumour incidence was related to exposure to a transient environmental agent.

METHODS

Information was extracted on individuals aged 0-14 years, diagnosed with a CNS tumour between the 1st January 1974 and 31st December 2006 from the Yorkshire Specialist Register of Cancer in Children and Young People. Ordnance Survey eight-digit grid references were allocated to each case with respect to addresses at the time of birth and the time of diagnosis, locating each address to within 0.1 km. The following diagnostic groups were specified a priori for analysis: ependymoma; astrocytoma; primitive neuroectodermal tumours (PNETs); other gliomas; total CNS tumours. We applied the K-function method for testing global space-time clustering using fixed geographical distance thresholds. Tests were repeated using variable nearest neighbour (NN) thresholds.

RESULTS

There was statistically significant global space-time clustering for PNETs only, based on time and place of diagnosis (P = 0.03 and 0.01 using the fixed geographical distance and the variable NN threshold versions of the K-function method respectively).

CONCLUSIONS

There was some evidence for a transient environmental component to the aetiology of PNETs. However, a possible role for chance cannot be excluded.

Infectious exposure in the first years of life and risk of central nervous system tumours in children: analysis of birth order, childcare attendance and seasonality of birth

Background:

An infective, mostly viral basis has been found in different human cancers. To test the hypothesis of a possible infectious aetiology for central nervous system (CNS) tumours in children, we investigated the associations with proxy measures of exposure to infectious disease.

Methods:

In a large case–control study nested in the populations of Denmark, Norway, Sweden, and Finland of 4.4 million children, we studied the association of birth order and seasonal variation of birth with subsequent risk for CNS tumours. We identified 3983 children from the national cancer registries, and information on exposure was obtained from the high-quality national administrative health registries. We investigated the association between childcare attendance during the first 2 years of life and the risk for CNS tumours in a subset of Danish children with CNS tumours, using information from the Danish Childcare database.

Results:

We observed no association between birth order and risk of CNS tumours overall (odds ratio (OR) for second born or later born vs first born, 1.03; 95% confidence interval (CI), 0.96–1.10) or by histological subgroup, and children with CNS tumours did not show a seasonal variation of birth that was distinct from that of the background population. Childcare attendance compared with homecare showed a slightly increased OR (1.29; 95% CI, 0.90–1.86) for CNS tumours, with the highest risk observed in children attending a crèche. The strongest association was observed for embryonal CNS tumours. We found no effect of age at enrolment or duration of enrolment in childcare.

Conclusion:

These results do not support the hypothesis that the burden of exposure to infectious disease in early childhood has an important role in the aetiology of paediatric CNS tumours.

Season of birth and risk for adult onset glioma

Adult onset glioma is a rare cancer which occurs more frequently in Caucasians than African Americans, and in men than women. The etiology of this disease is largely unknown. Exposure to ionizing radiation is the only well established environmental risk factor, and this factor explains only a small percentage of cases. Several recent studies have reported an association between season of birth and glioma risk. This paper reviews the plausibility of evidence focusing on the seasonal interrelation of farming, allergies, viruses, vitamin D, diet, birth weight, and handedness. To date, a convincing explanation for the occurrence of adult gliomas decades after a seasonal exposure at birth remains elusive.

Seasonality of birth in children with central nervous system tumours in Denmark, 1970-2003

We investigated possible seasonal variation of births among children <20 years with a central nervous system tumour in Denmark (N=1640), comparing them with 2,582,714 children born between 1970 and 2003. No such variation was seen overall, but ependymoma showed seasonal variation.

Space-time clustering of glioma cannot be attributed to specific histological subgroups

We previously showed that infectious exposures may be involved in the aetiology of adult glioma, by analysing for space-time clustering using population-based data from the South of the Netherlands. Here we extended these analyses and describe in detail the space-time clustering patterns in glioma subgroups, gender and age-categories. Knox tests for space-time interactions between cases were applied with fixed thresholds of close in space, <5 km, and close in time, <1 year apart. We used the spatial coordinates of the addresses at diagnosis in the analyses. Tests were repeated replacing geographical distance with distance to the Nth nearest neighbour. N was chosen such that the mean distance was 5 km. Data were also analysed by a second order procedure based on K-functions. There was only statistically significant space-time clustering for oligodendroglioma. Clustering was present for adults aged 30-54 years and was more pronounced among males. Given the low prior probability of an infectious aetiology for this specific subgroup, these results should probably be interpreted as false-positive. We conclude that space-time clustering of glioma cannot be attributed to a specific glioma subgroup. The observed clustering in our previous study is therefore probably an overall effect within and between glioma subgroups.

Early infection and risk of childhood brain tumors (Canada)

OBJECTIVE

Up to 15% of human cancers can be attributed to infections. Currently there are no known associations between infective agents and childhood brain tumors. We explored childhood brain tumor risk associated with a variety of indicators of infection during gestation and childhood.

METHODS

Two hundred and seventy-two cases of childhood brain tumor diagnosed in children less then 15 years of age in the province of Quebec between 1980 and 1999 were included in the study. An equal number of sex and age matched population based controls were recruited from family allowance or provincial health insurance files. Conditional logistic regression was used to estimate the risk of developing childhood brain tumors associated with self-reported exposure to infection.

RESULTS

Childhood brain tumor risk was weakly to moderately elevated after maternal reported exposure to several indicators of infection: use of antibiotics during gestation (OR = 1.7, 95% CI = 0.8-3.6) or childhood (OR = 1.4, 95% CI = 0.7-2.9), removal of tonsils, adenoids or appendix (OR = 1.2, 95% CI = 0.6-2.4), having siblings (OR = 1.4, 95% CI = 0.9-2.3), and being at least second born (OR = 1.7, 95% CI = 1.2-2.4). Moreover, childhood brain tumor risk was reduced for some subjects who were breastfed or attended daycare for more than 1 year. Risk varied by sex, age at diagnosis and tumor type.

CONCLUSION

Childhood brain tumor risk may be associated with exposure to infective agents.

Space–time clustering patterns of gliomas in the Netherlands suggest an infectious aetiology

To test the hypothesis that infectious exposures may be involved in glioma aetiology, we have analysed space-time clustering and seasonal variation using population-based data from the South of The Netherlands between 1983 and 2001. Knox tests for space-time interactions between cases were applied, with spatial coordinates of the addresses at time of diagnosis, and with distance to the Nth nearest neighbour. Data were also analysed by a second order procedure based on K-functions. Tests for heterogeneity and Edwards' test for sinusoidal variation were applied to examine seasonal variation of incidence. There was statistically significant space-time clustering in the Eastern, but not in the Western part of the region. Clustering was only present in adults, particularly in less densely populated areas. There was no evidence for seasonal variation. The results support a role for infectious exposures in glioma aetiology that may act preferentially in certain geographical areas.

Is there a common aetiology for certain childhood malignancies? Results of cross-space-time clustering analyses

We previously demonstrated significant space-time clustering amongst cases of childhood leukaemia (in particular acute lymphoblastic leukaemia (ALL)), central nervous system (CNS) tumour (especially astrocytoma), soft tissue sarcoma and Wilms' tumour. We hypothesised that there may be common aetiological mechanisms between some of these diagnostic groups. To test this hypothesis we analysed for cross-space-time clustering between these diagnostic groups, using population-based data from north-west England. Data were examined by a second-order procedure based on K-functions. Reference points in time and space were dates and addresses at birth and diagnosis. The results showed statistically significant (P < 0.05) cross-clustering between cases of leukaemia and CNS tumour and between cases of ALL and astrocytoma. There was no statistically significant cross-clustering of Wilms' tumours and soft tissue sarcomas with any other malignancy. In conclusion, these findings are consistent with common, possibly infectious, aetiological mechanisms for childhood leukaemia (particularly ALL) and CNS tumours (particularly astrocytoma).

Childhood cancer mortality in relation to the St Lucie nuclear power station

An unusual county-wide excess of childhood cancers of brain and other nervous tissue in the late 1990s in St Lucie County, Florida, prompted the Florida Department of Health to conduct a case-control study within the county assessing residential chemical exposures. No clear associations were found, but claims were then made that the release of radioactive substances such as strontium 90 from the St Lucie nuclear power station, which began operating in 1976, might have played a role. To test the plausibility of this hypothesis, we extended by 17 years a previous study of county mortality conducted by the National Cancer Institute. Rates of total cancer, leukaemia and cancer of brain and other nervous tissue in children and across all ages in St Lucie County were evaluated with respect to the years before and after the nuclear power station began operation and contrasted with rates in two similar counties in Florida (Polk and Volusia). Over the prolonged period 1950-2000, no unusual patterns of childhood cancer mortality were found for St Lucie County as a whole. In particular, no unusual patterns of childhood cancer mortality were seen in relation to the start-up of the St Lucie nuclear power station in 1976. Further, there were no significant differences in mortality between the study and comparison counties for any cancer in the time period after the power station was in operation. Relative rates for all childhood cancers and for childhood leukaemia were higher before the nuclear facility began operating than after, while rates of brain and other nervous tissue cancer were slightly lower in St Lucie County than in the two comparison counties for both time periods. Although definitive conclusions cannot be drawn from descriptive studies, these data provide no support for the hypothesis that the operation of the St Lucie nuclear power station has adversely affected the cancer mortality experience of county residents.

Epidemiology of brain tumors in childhood--a review

Malignant brain tumors are the leading cause of cancer death among children and the second most common type of pediatric cancer. Despite several decades of epidemiologic investigation, the etiology of childhood brain tumors (CBT) is still largely unknown. A few genetic syndromes and ionizing radiation are established risk factors. Many environmental exposures and infectious agents have been suspected of playing a role in the development of CBT. This review, based on a search of the medical literature through August 2003, summarizes the epidemiologic evidence to date. The types of exposures discussed include ionizing radiation, N-nitroso compounds (NOC), pesticides, tobacco smoke, electromagnetic frequencies (EMF), infectious agents, medications, and parental occupational exposures. We have chosen to focus on perinatal exposures and review some of the recent evidence indicating that such exposures may play a significant role in the causation of CBT. The scientific community is rapidly learning more about the molecular mechanisms by which carcinogenesis occurs and how the brain develops. We believe that advances in genetic and molecular biologic technology, including improved histologic subtyping of tumors, will be of huge importance in the future of epidemiologic research and will lead to a more comprehensive understanding of CBT etiology. We discuss some of the early findings using these technologies.

Measles virus: evidence of an association with Hodgkin's disease

The quest for an infectious agent that may account for cases of Hodgkin's disease (HD) especially in young adults has proven vain until lately. We have recently reported findings that suggested the presence of measles virus (MV) antigens and MV RNA in the tissues of patients with HD. Support for an association between MV and HD has been provided by recent epidemiological findings relating the occurrence of HD to exposure to measles in pregnancy and the perinatal period. We now present further evidence of this putative association based on immunohistochemical, reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridisation studies (ISH) on HD tissues. Biopsies from 82 (54.3%) of our cohort of 154 patients showed a positive immunostain with at least two of the anti-measles antibodies used. Latent membrane protein-1 immunostaining for Epstein-Barr virus was positive in 46 (31.1%) of the patients examined. Reverse transcriptase-PCR and ISH for measles RNA were positive in seven and 10 of 28 patients, respectively. Preliminary clinicopathological associations between MV and HD are noted in this study, but no causal relationship can be claimed at this stage.

Childhood cancer in relation to infections in the community during pregnancy and around the time of birth

In a retrospective cohort study of 404,106 live births in the northern region of England, 1975-1986, we investigated whether higher levels of community infections during the mother's pregnancy and in early life were risk factors for cancer, by diagnostic group (leukaemia and non-Hodgkin's lymphoma, Hodgkin's disease, brain/spinal tumours, neuroblastoma, other tumours), diagnosed 1975-2001 under age 15 years. Logistic regression was used to relate risk to measures of community infections (measles, respiratory and other infections) in 3 prenatal and 2 postnatal quarters. There was an increased risk of Hodgkin's disease among children exposed around birth to higher levels of measles (odds ratio for trend = 2.3, 95% confidence interval 1.3-4.2, p = 0.01). For other diagnostic groups, there was no consistent evidence of an association between risk and exposure to infections. Although the significant association observed for Hodgkin's disease may be a chance finding, consequent to multiple hypothesis testing or the ecologic nature of the study, it is consistent with other recent epidemiologic results suggesting that the risk of Hodgkin's disease may be associated with exposure to infections.