Inverse Association between Prediagnostic IgE Levels and the Risk of Brain Tumors: A Systematic Review and Meta-Analysis

AllergoOncology: Biomarkers and refined classification for research in the allergy and glioma nexus-A joint EAACI-EANO position paper

Epidemiological studies have explored the relationship between allergic diseases and cancer risk or prognosis in AllergoOncology. Some studies suggest an inverse association, but uncertainties remain, including in IgE-mediated diseases and glioma. Allergic disease stems from a Th2-biased immune response to allergens in predisposed atopic individuals. Allergic disorders vary in phenotype, genotype and endotype, affecting their pathophysiology. Beyond clinical manifestation and commonly used clinical markers, there is ongoing research to identify novel biomarkers for allergy diagnosis, monitoring, severity assessment and treatment. Gliomas, the most common and diverse brain tumours, have in parallel undergone changes in classification over time, with specific molecular biomarkers defining glioma subtypes. Gliomas exhibit a complex tumour-immune interphase and distinct immune microenvironment features. Immunotherapy and targeted therapy hold promise for primary brain tumour treatment, but require more specific and effective approaches. Animal studies indicate allergic airway inflammation may delay glioma progression. This collaborative European Academy of Allergy and Clinical Immunology (EAACI) and European Association of Neuro-Oncology (EANO) Position Paper summarizes recent advances and emerging biomarkers for refined allergy and adult-type diffuse glioma classification to inform future epidemiological and clinical studies. Future research is needed to enhance our understanding of immune-glioma interactions to ultimately improve patient prognosis and survival.

Alkylating agents are possible inducers of glioblastoma and other brain tumors

Epidemiological evidence of an association between exposure to chemical carcinogens and an increased risk for development of glioblastoma (GBM) is limited to weak statistical associations in cohorts of firefighters, farmers, residents exposed to air pollution, and soldiers exposed to toxic chemicals (e.g., military burn pits, oil-well fire smoke). A history of ionizing radiation therapy to the head or neck is associated with an increased risk of GBM. Ionizing radiation induces point mutations, frameshift mutations, double-strand breaks, and chromosomal insertions or deletions. Mutational profiles associated with chemical exposures overlap with the broad mutational patterns seen with ionizing radiation. Data on 16 agents (15 chemicals and radio frequency radiation) that induced tumors in the rodent brain were extracted from 602 Technical Reports on 2-years cancer bioassays found in the National Toxicology Program database. Ten of the 15 chemical agents that induce brain tumors are alkylating agents. Three of the 15 chemical agents have idiosyncratic structures and might be alkylating agents. Only two of the 15 chemical agents are definitively not alkylating agents. The rat model is thought to be of possible relevance to humans suggesting that exposure to alkylating chemicals should be considered in epidemiology studies on GBM and other brain tumors.

Prediagnostic biomarkers for early detection of glioma—using case–control studies from cohorts as study approach

Background

Understanding the trajectory and development of disease is important and the knowledge can be used to find novel targets for therapy and new diagnostic tools for early diagnosis.

Methods

Large cohorts from different parts of the world are unique assets for research as they have systematically collected plasma and DNA over long-time periods in healthy individuals, sometimes even with repeated samples. Over time, the population in the cohort are diagnosed with many different diseases, including brain tumors.

Results

Recent studies have detected genetic variants that are associated with increased risk of glioblastoma and lower grade gliomas specifically. The impact for genetic markers to predict disease in a healthy population has been deemed low, and a relevant question is if the genetic variants for glioma are associated with risk of disease or partly consist of genes associated to survival. Both metabolite and protein spectra are currently being explored for early detection of cancer.

Conclusions

We here present a focused review of studies of genetic variants, metabolomics, and proteomics studied in prediagnostic glioma samples and discuss their potential in early diagnostics.

Immune factors preceding diagnosis of glioma: a Prostate Lung Colorectal Ovarian Cancer Screening Trial nested case-control study

Background

Epidemiological studies of adult glioma have identified genetic and environmental risk factors, but much remains unclear. The aim of the current study was to evaluate anthropometric, disease-related, and prediagnostic immune-related factors for relationship with glioma risk.

Methods

We conducted a nested case–control study among the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) Screening Trial. One hundred and twenty-four glioma cases were identified and each matched to four controls. Baseline characteristics were collected at enrollment and were evaluated for association with glioma status. Serum specimens were collected at yearly intervals and were analyzed for immune-related factors including TGF-β1, TNF-α, total IgE, and allergen-specific IgE. Immune factors were evaluated at baseline in a multivariate conditional logistic regression model, along with one additional model that incorporated the latest available measurement.

Results

A family history of glioma among first-degree relatives was associated with increased glioma risk (OR = 4.41, P = .002). In multivariate modeling of immune factors at baseline, increased respiratory allergen-specific IgE was inversely associated with glioma risk (OR for allergen-specific IgE > 0.35 PAU/L: 0.59, P = .03). A logistic regression model that incorporated the latest available measurements found a similar association for allergen-specific IgE (P = .005) and showed that elevated TGF-β1 was associated with increased glioma risk (P-value for trend <.0001).

Conclusion

The results from this prospective prediagnostic study suggest that several immune-related factors are associated with glioma risk. The association observed for TGF-β1 when sampling closer to the time of diagnosis may reflect the nascent brain tumor’s feedback on immune function.

IgE deficiency and prior diagnosis of malignancy: Results of the 2005-2006 National Health and Nutrition Examination Survey

BACKGROUND

Data on patients from tertiary-level health care facilities suggest that IgE-deficient (IgE <2.5 kU/L) patients have high rates of prior malignant tumors.

OBJECTIVE

To investigate the association between IgE levels and diagnosis of malignancy in non-institution-associated patients using the 2005-2006 US National Health and Nutrition Examination Survey (NHANES) cohort.

METHODS

All individuals with available IgE levels and known prior diagnosis of malignancy were divided into 4 groups: IgE deficient (IgE, <2.5 kU/L), normal IgE levels (2.5-100 kU/L), high IgE levels (100-1,000 kU/L), and very high IgE levels (≥1,000 kU/L). Rates of malignancy were compared among groups.

RESULTS

Of 4,488 individuals with data on IgE levels and malignancy status, 7.4% had a prior diagnosis of cancer. The rate of prior malignancy was significantly higher in the IgE-deficient group (12.6%) compared with individuals with high (6.7%, P = .04) and very high IgE levels (5.3%, P = 0.04). In the IgE-deficient group, only 3 patients had a diagnosis of malignancy within 3 years of IgE measurement. A mean (SD) of 10.3 (9.6) years elapsed between the time of malignancy diagnosis and IgE collection time; therefore, active neoplasm or recent chemotherapy was less likely to explain the very low IgE levels. Types of malignancies in the IgE-deficiency group included breast cancer (n = 6), nonmelanoma or unknown skin cancer (n = 3), uterine cancer (n = 2), cervical cancer (n = 1), lung cancer (n = 1), prostate cancer (n = 1), and hematologic cancer (n = 1).

CONCLUSION

In this non-institution-based cohort, IgE deficiency was associated with a higher rate of prior diagnosis of malignancies compared with individuals with high or very high IgE levels. Prospective studies are essential to better evaluate the association between IgE levels and risk of cancer.

Allergy is associated with reduced risk of glioma: A meta-analysis

BACKGROUND

Increasing evidences suggest that allergy may reduce the risk of glioma, so it is necessary to perform an up-to-data literature search and investigate this relationship by meta-analysis.

METHODS

We identified the included studies by searching PubMed and Web of Science and excluding irrelevant or ineligible articles. Nineteen studies from 15 articles, including 8435 cases and 118,719 controls, were selected for data extraction and synthesis.

RESULTS

Pooled outcomes showed that there was an inverse association between allergy and risk of glioma (OR=0.64, 95% CI=0.52-0.78, P<0.001). Meanwhile, asthma and eczema would reduce the risk of glioma by 33% and 23% (OR=0.67, 95% CI=0.59-0.75, P<0.001; OR=0.77, 95% CI=0.68-0.86, P<0.001), respectively. Sensitivity analyses confirmed the stability of these findings. Besides, no publication biases were detected regarding all the investigations.

CONCLUSIONS

Overall or specific allergy is protective against glioma. More prospective cohort studies or molecular laboratory experiments are warranted to elucidate the causation and key mechanism.