A biomarker is a biochemical feature used to measure the progress of disease or the effects of treatment. More specifically, a biomarker, also known as a biological marker, is a substance used as an indicator of a biological state. A biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, and used to determine if any changes are natural, or a positive or negative result of treatment. Specifically, a biomarker measures whether changes are a pathogenic processes, or pharmacologic responses to a therapeutic intervention. It is used in many scientific fields to prove or disprove medical therapies.