PT - JOURNAL ARTICLE AU - Deitz, Anne C. AU - Rothman, Nathanial AU - Rebbeck, Timothy R. AU - Hayes, Richard B. AU - Chow, Wong-Ho AU - Zheng, Wei AU - Hein, David W. AU - GarcĂ­a-Closas, Montserrat TI - Impact of Misclassification in Genotype-Exposure Interaction Studies: Example of <em>N</em>-Acetyltransferase 2 (<em>NAT2</em>), Smoking, and Bladder Cancer DP - 2004 Sep 01 TA - Cancer Epidemiology Biomarkers &amp; Prevention PG - 1543--1546 VI - 13 IP - 9 4099 - http://cebp.aacrjournals.org/content/13/9/1543.short 4100 - http://cebp.aacrjournals.org/content/13/9/1543.full SO - Cancer Epidemiol Biomarkers Prev2004 Sep 01; 13 AB - Errors in genotype determination can lead to bias in the estimation of genotype effects and gene-environment interactions and increases in the sample size required for molecular epidemiologic studies. We evaluated the effect of genotype misclassification on odds ratio estimates and sample size requirements for a study of NAT2 acetylation status, smoking, and bladder cancer risk. Errors in the assignment of NAT2 acetylation status by a commonly used 3-single nucleotide polymorphism (SNP) genotyping assay, compared with an 11-SNP assay, were relatively small (sensitivity of 94% and specificity of 100%) and resulted in only slight biases of the interaction parameters. However, use of the 11-SNP assay resulted in a substantial decrease in sample size needs to detect a previously reported NAT2-smoking interaction for bladder cancer: 1,121 cases instead of 1,444 cases, assuming a 1:1 case-control ratio. This example illustrates how reducing genotype misclassification can result in substantial decreases in sample size requirements and possibly substantial decreases in the cost of studies to evaluate interactions.