A biomarker's a substance used as an indicator of a biologic state. It's a characteristic that's objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. Types Biomarkers validated by genetic and molecular biology methods can be classified into three types. Type 0 - Natural history markers Type 1 - Drug activity markers Type 2 - Surrogate markers A biomarker can be any kind of molecule i… (More on Biomarker)