Biomarkers are measurable indicators of biological processes or responses to treatment. Identification and validation of biomarkers is a critical step in preclinical studies, as they provide a way to objectively measure the effects of a substance on biological systems, predict therapeutic outcomes, and monitor the progression of diseases or toxicities.

The identification of biomarkers can involve a range of techniques, including genomics, proteomics, metabolomics, and imaging. Once potential biomarkers have been identified, they need to be validated through further studies to determine their specificity, sensitivity, and predictive value.

The validation of biomarkers involves testing their ability to accurately predict clinical outcomes, such as disease progression or response to treatment. Biomarkers must also be validated in different animal models and human tissues to ensure their relevance and utility across different species and diseases.

The selection of appropriate biomarkers is critical to the success of preclinical studies. The selected biomarkers should be specific to the biological process or response being studied, and should be measurable with high sensitivity and accuracy. The biomarkers should also be validated in a range of experimental conditions and validated across different animal models and human tissues to ensure their reliability and relevance.

Overall, biomarker identification and validation are essential steps in preclinical studies, as they provide a means to objectively measure the effects of a substance on biological systems and predict clinical outcomes. The selection of appropriate biomarkers should be based on a comprehensive understanding of the biological process or response being studied, and the biomarkers should be validated across a range of experimental conditions and animal models to ensure their reliability and relevance.