Modulation of gene expression is of paramount importance in the mechanisms of drug-induced toxicity, and major efforts are being made to determine the relevance of gene expression in response to drug exposure. DNA arrays offer the unique opportunity to explore the simultaneous gene expression of literally thousands of genes, but their cost-effective use require a rational choice in gene selection and access to a clone library to produce tailor-made and merit-based arrays. In conjunction with other molecular endpoints, reliable predictions of drug safety are now feasible at early stages in drug development.
