GENOMICS AND ITS ROLE IN CANCER RISK ASSESSMENT

Conventional rodent toxicity studies characterize adverse effects of a chemical primarily on apical endpoints such as clinical signs or pathological states. Evidence of organ toxicity in the form of an apical endpoint does not always provide mechanistic understanding of the toxicity involved (see Chapter 13). The exposure of rodents in a cancer bioassay model can result in species-specific responses that are not relevant to humans (e.g., alpha2u-globulin-induced rat renal tumors) (see Chapter 18) (EPA 1991). Rodents may also have increased sensitivity to a particular toxicity pathway relative to humans (e.g., disruption of thyroid homeostasis and thyroid follicular tumors in rodents) (EPA 1998 I ARC 2001). There are rodent responses to chemical treatment in tissues where there is a high spontaneous incidence to develop 

Cancer Risk Assessment, edited by Ching-Hung Hsu and Todd Stedeford Copyright 2010 John Wiley Sons, Inc. 

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CHAPTER 22 GENOMICS AND ITS ROLE IN CANCER RISK ASSESSMENT... 

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