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  - García-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 & 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.