The existence of living organisms or biological processes, a particular disease state, or a fragment of DNA sequence can indicate biomarkers. Locations of a particular molecule (cellular or subcellular, tissue or organ locations) can also be a biomarker.
Biomarkers ideal for diagnosis should have great sensitivity, specificity, and accuracy in reflecting total disease burden. A tumor marker should also be prognostic of outcome and predictive of tumor recurrence and effectiveness of anti-cancer treatments.
Biomarkers for screening purposes must be highly specific, minimizing false positive and negative results. The biomarker must be able to clearly reflect the early stage of disease and it must be easily detected without complicated medical procedures. The disease markers released to serum and urine are good targets for application of early screening. The method for screening should be cost effective. Biomarkers are commonly detected through blood, urine, other body fluids, and tissue samples.
Biomarkers play a major role in medicinal biology. Biomarkers bring the future things in our hand by helping in early diagnosis, disease prevention, drug target identification, drug response etc. Several disease-based biomarkers had been identified for many diseases such as serum LDL for cholesterol, blood pressure, P53 gene and MMPs for cancer. Gene based biomarkers are found to be effective and acceptable markers in the present scientific world.