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Background: The effect on childhood brain tumor risk from medical history during a sensitive period of neural development remains unknown. Aims: Our aim was to investigate whether pre/peri- or post...

The aim of this study was to characterize the population frequency of SLCO1B1 polymorphic variants in three distinct healthy Asian populations, namely Chinese (n = 100), Malay (n = 100) and Indian (n = 100), and to explore the association between haplotype-tagged single nucleotide polymorphisms (htSNPs) on hepatic SLCO1B1 mRNA expression.The distribution of polymorphic variants in the SLCO1B1 gene at eight loci that spanned approximately 48 kb was investigated in the three different Asian ethnic groups and in 32 non-cancerous liver tissues from Chinese patients.Of the 26 polymorphisms screened, we found eight polymorphic variants that differed in genotypic and allelic frequencies between the Chinese, Malay and Indian populations. Significant interethnic differences were observed in the genotype frequency distributions across the promoter SNP [g.-11187GA (P = 0.030)] as well as three coding region SNPs [c.388GA (P0.001); c.571TC (P0.001); c.597CT (P0.001)] in the healthy subjects. Haplotype analysis revealed 12 different haplotypes in both the Chinese and Malay populations and 18 haplotypes in the Indian population. In both the Malay and Indian populations, the htSNPs were c.388AG, c.571TC and c.597CT, whereas in the Chinese population they were g.-11187GA, c.388AG and c.597CT. The c.388AG and c.597CT htSNPs accounted for more than 70% of the variations between the three major haplotypes in each Asian ethnic group. In terms of the c.388AG htSNPs, genotypic-phenotypic association analyses revealed that there was no effect on SLCO1B1 expression in hepatic tissues; in addition, no genotypic-phenotypic associations were evident with regards to the c.597CT htSNP.Future studies should investigate the phenotypic effects of the c.388AG htSNP on the disposition of OATP1B1 substrates in Asian populations.

BACKGROUND Previous studies have evaluated the effect of medical diagnostic radiation on brain tumors. Recent cohort studies have reported an increased risk associated with exposure to head CT scans. METHODS Information regarding medical conditions, including prenatal and postnatal exposure to medical diagnostic radiation, was obtained from CEFALO, a multicenter case-control study performed in Denmark, Norway, Sweden, and Switzerland through face-to-face interview. Eligible cases of childhood and adolescent brain tumors (CABT) were ages 7 to 19 years, diagnosed between January 1, 2004 and August 31, 2008, and living in the participating countries (n = 352). The cases were matched by age, sex, and region to 646 population-based controls. RESULTS Prenatal exposure to medical diagnostic radiation and postnatal exposure to X-rays were not associated with CABTs. A higher risk estimate of CABTs, although not statistically significant, was found for exposure to head CT scan (OR, 1.86; 95% confidence interval, 0.82-4.22). The associations with head injury, febrile seizure, fever in the first 12 weeks, and general anesthesia were close to unity. CONCLUSIONS Prenatal or postnatal medical conditions, including medical diagnostic radiation, were not associated with CABTs. On the basis of small numbers of exposed children, we observed a nonsignificant increased risk for CT scans of the head. IMPACT We have presented additional evidence, suggesting that exposure to head CT scan may be associated with the occurrence of CABTs. Cancer Epidemiol Biomarkers Prev; 26(1); 110-5. ©2016 AACR.