American Journal of Epidemiology Advance Access originally published online on March 7, 2008
American Journal of Epidemiology 2008 167(10):1260-1267; doi:10.1093/aje/kwn012
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PRACTICE OF EPIDEMIOLOGY |
Buccal Swabs and Treated Cards: Methodological Considerations for Molecular Epidemiologic Studies Examining Pediatric Populations
1 Children's Cancer Institute Australia for Medical Research, Randwick, New South Wales, Australia
2 Department of Hematology and Oncology, Starship Children's Hospital, Auckland, New Zealand
3 Department of Oncology, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
4 Center for Children's Cancer and Blood Disorders, Sydney Children's Hospital, Randwick, New South Wales, Australia
5 Telethon Institute for Child Health Research, Center for Child Health Research, University of Western Australia, Perth, Western Australia, Australia
Correspondence to Dr. Lesley Ashton, Molecular Epidemiology Group, Children's Cancer Institute Australia for Medical Research, P.O. Box 81, Randwick, NSW 2031, Australia (e-mail: lashton{at}ccia.unsw.edu.au).
Received for publication June 26, 2007. Accepted for publication January 14, 2008.
Self-collection of buccal cells provides a noninvasive method for obtaining biologic samples for genetic analyses in pediatric studies. Nevertheless, low yields, microbial contamination, and degradation of buccal samples present challenges for epidemiologic studies incorporating genetic investigations. The aims of this study were to compare the quality and yield of DNA extracted from buccal specimens with BuccalAmp swabs (Epicenter BioTechnologies, Madison, Wisconsin) or FTA cards (Whatman, Inc., Clifton, New Jersey) and to investigate the use of whole-genome amplification (WGA) for increasing DNA yields for single nucleotide polymorphism analyses. Buccal specimens were collected from 55 children with acute lymphoblastic leukemia and 52 control children without acute lymphoblastic leukemia in New South Wales, Australia, in 2003–2004. Real-time polymerase chain reaction was used to evaluate polymorphisms in the genes encoding the cytochrome p450 enzyme CYP3A4 (CYP3A4 A392G, also known as CYP3A4*1B) and the steroid xenobiotic receptor (SXR C25385T). Results showed that DNA could be isolated from buccal specimens collected by use of both methods and that yields could be substantially improved with WGA without introducing genotyping error. However, DNA quality was poorer in samples collected by BuccalAmp swabs, and the presence of polymerase chain reaction inhibitors in these samples reduced the sensitivity of quantitative real-time PCR analysis. These findings show that different methods for collecting buccal samples impact on the downstream success of genetic investigations and influence DNA quality after WGA.
DNA; epidemiologic methods; epidemiology, molecular; genome; mouth mucosa; pediatrics
Abbreviations: MDA, multiple displacement amplification; PCR, polymerase chain reaction; SNP, single nucleotide polymorphism; WGA, whole-genome amplification