Genetic variation in p53 and ATM haplotypes and risk of glioma and meningioma

BACKGROUND

P53 and ATM are central checkpoint genes involved in the repair of DNA damage after ionising irradiation, which has been associated with risk of brain tumours. Therefore, we tested the hypothesis that polymorphisms and haplotypes in p53 and ATM could be associated with glioma and meningioma risk.

MATERIAL AND METHODS

Six hundred and eighty glioma cases (298 glioblastoma (GBM)), 503 meningioma cases, and 1555 controls recruited in the Nordic-UK Interphone study, were analysed in association with three polymorphisms in p53 (rs2287499, rs1042533, rs1625895) and five polymorphisms in ATM ( rs228599, rs3092992, rs664143, rs170548, rs3092993). Haplotypes were constructed using the HAPLOSTAT program.

RESULTS

The global statistical test of glioblastoma and p53 haplotypes was p = 0.02. The haplotype analysis on glioblastoma revealed the 1-2-2 haplotype (promotor-codon72-intron 6) had a frequency of 6.1% in cases compared with 9.8% in controls (p = 0.003). The 1-2-1 haplotype was significantly more frequent in GBM cases, 10.2%, than in controls, 7.3% (p = 0.02). The haplotype analysis in ATM revealed an increased frequency of the 1-1-1-2-1 haplotype in meningioma cases (33.8%) compared with controls (30.3%) (p = 0.03). The 2-1-2-1-1 haplotype had a lower frequency in meningioma cases (36.1%) than controls (40.7%) (p = 0.009).

CONCLUSIONS

This study found both positive and negative associations of haplotypes in p53 for glioblastoma and ATM for meningioma. This study provides new data that could add to our understanding of brain tumour susceptibility.

Epilepsy as a risk factor for cancer

AIM

Epilepsy and long term use of antiepileptic drugs have been suggested to be associated with an increased risk of cancer. The authors therefore set out to analyse previous diagnosis of epilepsy as a risk factor for certain cancer forms in a case control study.

METHODS

Incident cases of leukaemia, lymphoma, myeloma, and pancreatic cancer were identified from the Swedish Cancer Registry 1987-99, a total of 52 861 cases. Controls (n = 137 485) were randomly selected from the Swedish Population Registry stratified on age, sex, and year of cancer diagnosis. Cases and controls were linked to the Swedish Hospital Discharge Registry for 1969-99 to identify individuals with first time hospital discharge for epilepsy.

RESULTS

While an epilepsy diagnosis the same year as a cancer diagnosis carried an increased risk of non-Hodgkin's lymphoma (OR = 2.89, 95% CI 1.89 to 4.41), Hodgkin's disease (OR = 4.77, 95% CI 1.77 to 13.30), leukaemia (OR = 2.55, 95% CI 1.50 to 4.32), acute myeloid leukaemia (OR = 3.65, 95% CI 1.68 to 7.93), and pancreatic cancer (OR = 2.05, 95% CI 1.22 to 3.45), the authors found no support for an association between discharge with a diagnosis of epilepsy two years or more before the diagnosis of cancer and an increased risk of any of the types of cancer included in this analysis. The lack of association was also evident for individuals with an epilepsy diagnosis preceding malignancy/reference year by >10 years.

CONCLUSIONS

Clinical examinations prompted by seizure onset probably mainly explain the observed association between epilepsy diagnoses the year before a cancer diagnosis. However, these results lend no support to the suggestion that epilepsy, and presumably long term exposure to antiepileptic drugs, is associated with an increased risk of the types of cancer included in the present study.

Dietary calcium consumption and astrocytic glioma: the San Francisco Bay Area Adult Glioma Study, 1991-1995

Previous studies suggest an association between calcium consumption and glioma risk. In the present study, we compare consumption of calcium and other dairy components and foods (cholesterol, fat, protein, calories, milk, and cheese) of 337 astrocytic glioma case patients with 450 controls from the San Francisco Bay Area Adult Glioma Study, 1991-1995. We use unconditional logistic regression models to estimate odds ratios (ORs) by gender controlling for age, education, and income. A statistically significant inverse association [p (trend) = 0.05] was observed for dietary calcium intake for women only [OR = 0.49, 95% confidence interval (CI) = 0.24-1.03 for highest vs. lowest quartile of consumption]. In addition, we observed elevated ORs for highest vs. lowest quartiles of cholesterol intake among women and men (OR = 2.07, 95% CI = 1.00-4.28 and OR = 1.75, 95% CI = 0.92-3.31, respectively). Calcium may exert a protective effect through its known roles in apoptosis, DNA repair, and inhibition of parathyroid hormone production. Recent evidence suggests that parathyroid hormone may influence growth and dedifferentiation of astrocytoma cells. Finally, circulating estradiol might directly stimulate intestinal absorption of calcium and may therefore explain why the inverse association of calcium intake and glioma is confined to women.