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Updated: Mar 25, 2026

In Vivo Alkaline Comet Assay and Enzyme-modified Alkaline Comet Assay for Measuring DNA Strand Breaks and Oxidative DNA Damage in Rat Liver
Published on: May 4, 2016
Multiple contrast type tests for the evaluation of animal carcinogenicity studies
1a Division of Biometrics-6, Office of Biostatistics, Office of Translational Sciences , Center for Drug Evaluation and Research, US Food and Drug Administration , Silver Spring , Maryland , USA.
Abstract:
The Cochran-Armitage (CA) test is frequently used for testing the dose-response relationship in tumor incidence. This test is based on a weighted linear regression of proportions. It is well known that the CA test lacks power for nonlinear tumor outcomes. For general shape of outcomes, Hothorn and Bretz (2000) proposed a multiple contrast (MC) test. This test suggests the use of the maximum over several single contrasts, where each of them is chosen appropriately to cover a specific dose-response shape. In this work, two new test procedures are proposed and they are compared to the CA and MC tests using power.
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