What are Biomarkers?

About Biomarkers:

• Biomarkers, short for ‘Biological Markers’ are a physical, chemical or biological characteristic that is present in the human body and measurable too.
• The WHO defines a biomarker as “any measurement reflecting an interaction between a biological system and a potential hazard, which may be chemical, physical or biological. The measured response may be functional and physiological, biochemical at the cellular level or a molecular interaction”.
• Experts also call them molecular markers and signature molecules. They are indispensable in diagnosing disease, prescribing the right medication, right dosage, and even while designing new drugs.
  • Biomarkers include biomolecules like carbohydrates, proteins, lipids, genes, DNA, RNA, platelets, enzymes, hormones, etc.
• Classification of Biomarkers:
  • Based on their source or location:
    • Molecular– have biophysical properties, which allow their measurements in biological samples such as blood plasma, serum, cerebrospinal fluid, bronchoalveolar lavage, biopsy, urinalysis, and faecal analysis
    • Radiographic– obtained from imaging studies, for example, bone mineral density
    • Histologic– reflect biochemical or molecular alteration in cells, tissues, or fluids; for example, the staging and grading of cancers
    • Physiologic– measures of body processes, for example, blood pressure, pulse rate, and heart rate
  • Based on roles/functions:
    • Susceptibility/Risk Biomarkers: Indicate the person’s likelihood of developing a particular disease or condition in the near or distant future. 
    • Diagnostic Biomarkers: These are used to detect or confirm a particular disease or condition.
    • Prognostic Biomarkers: In people who already are confirmed to have a disease, prognostic biomarkers can predict the likelihood of disease progression or relapse.
    • Monitoring Biomarkers: These biomarkers are used for one or all of these reasons: to assess the stage or condition of the disease, to measure the exposure to a particular drug and to measure exposure to an environmental agent. 
    • Predictive Biomarkers: These are used to identify individuals who have a higher likelihood of experiencing a strong outcome when exposed to a particular drug. This will help decide the treatment options.
    • Pharmacodynamic/Response Biomarkers: These reveal that a biological response has happened in patients exposed to a particular drug or environmental agent.