Biomarker: diagnosis and clinical utility

Biomarker is a biological molecule found in body fluid and other tissues. Biomarkers are beneficial for accessing the health condition of human and animals. Identification and estimation of biomarkers become prominence due to the development of modern technologies in the field of health science. There are varieties of biomolecules representing different physiological and pathological conditions of the body. These varieties of biomolecules included proteins, enzymes, receptors, nucleic acids, antibodies and peptides. Our cells are make up with biomolecules, when our cell metabolism or process alters, expression of different proteins or other associated molecules also shows alternation. The expression of some proteins or enzymes showed significantly higher in some conditions. The estimation of these biomolecules can be detected in the blood and other fluid of the body that may give the information of the organ or body conditions. A biomarker can also be a collection of alterations, such as gene expression, proteomic, and metabolomics signatures. Biomarkers can give an indication of normal biological processes, pathogenic processes, or pharmacological responses to a therapeutic or other health care intervention. Therefore, biomarker is gaining more popularity as analytical tool to assess the biological parameters for a rapid and comprehensive therapeutic analysis. In addition, biomarker measures can further be used for the development and evaluation of new therapies. Practically, these include tools and technologies which help in understanding the prediction, cause, diagnosis, progression, regression, or outcome of treatment of a particular disease. It can be considered as non-invasive tools, can be detected in the circulation (whole blood, serum, plasma), excretions or secretions (stool, urine, sputum, nipple discharge). Also, biomarkers can be called as Genetic which are inherited and detected as sequence variations in germ line DNA isolated from whole blood, sputum, or buccal cells. It can be identified as mutations in DNA derived from tumor tissue.

Biomarkers can be used for the assessment of risk factor of a disease, screening of cancers, distinguishing between benign and malignant tumours, determination of prognosis and prediction of cancer, and monitoring status of the disease.

Disease Diagnosis and prognosis: Biomarkers have been used for clinical diagnosis of multiple diseases for many years. For example, Troponin was used for the diagnosis of myocardial infarction, creatinine for renal insufficiency, similarly, amylase for pancreatitis.Biomarker based tests can confirm a clinical diagnosis and also provides information regarding prognosis of the disease. These diagnostic tests may enable identification of disease in the early stages before it can be diagnosed by other means, provides opportunities for prevention of disease progression that may reduce the direct and indirect costs of disease. Due to the objective values and convenience of measurement with automated technology in the modern era, the applications of biomarkers in biomedicine are gainingan important in diagnostic laboratories. Screening of genes related to breast or ovarian cancer may be used to identify the individuals at risk, providing an opportunity for these individuals to manage their disease risk.

Targeted therapy: Targeted agents are revolutionizing the cancer therapy. From monoclonal antibodies (MoAb) to small molecule inhibitors (SMIs) and immunoconjugates and other targeted agents are quickly migrating from bench to bedside. Rituximab, a MoAb against CD20, has essentially changed the natural history of diffuse large B cell lymphoma, and is effective in other B-cell disorders such as rheumatoid arthritis. Trastuzumab, a MoAb blocking Her2/neu, is an indispensable agent for positive breast cancer and metastatic gastric cancer. Bevacizumab, a MoAb binding vascular endothelial growth factor (VEGF), has been used for the treatment of colorectal, brain, kidney and non-small cell lung cancers.

Surrogate endpoint for clinical trials: The potential impact of biomarker-based tests in the clinical setting is substantial, especially in the context of chronic diseases. Chronic diseases such as diabetes, cancer, chronic respiratory disorders and dementia represents a significant and increasing socio-economic burden. For example, dementia affects 35.6 million people worldwide and the direct and indirect costs of dementia are estimated at USD 604 billion annually, accounting for ~1% of the world’s GDP. Within an aging and growing population, the number of people with dementia is projected to double by 2030 (65.7 million worldwide) and is estimated to triple by 2050 (115.4 million) (Wimo, 2010).Also, these are getting recognitions to serve as surrogate endpoints in cancer trials and timely helps to identify patients who will benefit from the specific targeted therapy agents such as BCR-ABL transcript level was recognized as a surrogate biomarker endpoint in ENESTnd.

Moreover, biomarkers have been used to replace time-consuming traditional endpoints by accelerating the translation of novel agents from bench to bedside. Clearly, more specific biomarkers will be implemented in the future clinical studies which will help to tailor patient’s best care in a new era of personalized medicine.

Estimation and identification of biomarkers invaded many good diagnostic laboratories for early diagnosis diseases. This helps in achieving the betterment of patient and proper control of diseases. Biomarkers also used for any epidemiological project or clinical trial. There is still a great scope for standardization of different biomarkers as a non-invasive tools for early diagnosis of different diseases which can significantly influence patient outcomes as well as welfare of the society. It is important for clinical, translational, and laboratory-based researchers to be alert for appropriate biomarker development in order to facilitate clinical useful of biomarkers.