A bio marker or biological marker, are defined as an indicator of a biological state of a living body. It is a characteristic that is measured and evaluated as an indicator of normal biological processes. In addition, they also help in pathogenic processes or pharmacologic responses to a therapeutic intervention. Bio markers help develop targeted therapies for diseases, screen and forecast diseases. They also respond to a treatment or monitor the patient. This article focuses on the role of bio markers in medical diagnosis.
Bio markers and their applications in healthcare
They play an essential role in disease detection. Bio markers have become one of the major driving forces of pharmaceutical research and drug development (Karley, 2011). Bio markers have not only helped to develop targeted therapies but also predict risks of cancer and many other genetic diseases. Furthermore, bio markers also forecast how well a person is likely to respond to any treatment, such as cancer or monitor the prognosis of the patient. Bio markers are used in several diseases including cancer, osteoarthritis, pulmonary diseases, sepsis, systemic sclerosis and others.
The use of bio markers was first described by Isaak-son in 1980 when he proposed urinary nitrogen as an independent measure of protein intake and it remains. Bio markers are classified into two large groups. One is bio markers of nutritional exposure and bio markers of nutritional status (Corella and Ordovs, 2015). However, compared to procedures such as radiology, cytology and endoscopy, the use of bio markers as cancer screening tests have several advantages. These advantages include; measurement using biological fluids like blood and urine for undergoing screening and lead to high compliance rates.
Application of bio markers in disease management
Bio markers study helps to improve the disease management in several ways, according to Jain, (2017);
- It provides a better understanding of pathomechanics of diseases.
- Helps in screening for the detection of early-stage disease in the asymptomatic population.
- To establish an unambiguous diagnosis and accurate description of the disease.
- Improve the prognosis identification.
- To provide a base for the development of therapeutics and monitoring of the disease with regards to the therapeutics being given.
- Identify the patients with a high chance of undesirable effects of treatment.
- It helps in posttreatment monitoring for prompt detection of recurrence and progressive disease or complications.
- Can determine response to specific therapies and select the drug that is most likely to produce a promising response in a given patient, usually know as personalized medicine.
Examples of bio marker in medical diagnosis
Cancer bio marker is gaining popularity and might be used as a “liquid biopsy” also called micro RNA (miRNA). Expression patterns of miRNAs’ are unique to individual tissues and differ between cancer and normal tissues. On the other hand, some miRNAs’ are over expressed or down regulated exclusively or preferentially in certain cancer types. Similarly, cholesterol, a fatty substance produced by the body, is a bio marker for heart disease. Bio markers tests help follow body processes and diseases in humans and animals. They can be used to predict how a patient will respond to a medicine or whether they have, or are likely to develop, a certain disease (Karley, 2011).
For many bio markers, automated assays are available, thus allowing the processing of large numbers of samples in a relatively short period of time. Tests for bio markers provide quantitative results with objective endpoints. Assays for bio markers are relatively cheap.
Recent advances in healthcare industry
In the recent years, knowledge about bio markers has increased. It has provided great opportunities for improving the management of patients by enhancing the efficiency of detection and efficacy of treatment. Recent technological advancement has enabled the examination of many potential bio markers and renewed interest in developing new bio markers. The current research areas of bio marker are widened and far-ranging that include toxicology, drug discovery, clinical markers of therapeutic index and efficacy, and others. New dimensions to the field of bio markers have been added by the pharmacogenomics, bioinformatics, and microbiome fields of study. Some of the techniques which are used for the discovery of bio markers are Genomic technology, Epigenetic technology, Glycomic technology, Proteomic technology, Bioinformatics, Metabolomics, and Lipidomics (Jain, 2017).
However, bio markers of cancer could include a broad range of biochemical entities, such as nucleic acids, proteins, sugars, lipids, and small metabolites, cytogenetic and cytokinetic parameters as well as whole tumor cells found in the body fluid. A comprehensive understanding of the relevance of each bio marker will be very important not only for diagnosing the disease reliably. They also help in the choice of multiple therapeutic alternatives currently available that is likely to benefit the patients. Bio markers too have great potential to influence the rate of success of clinical trials, identifying novel drug targets, and developing diagnostic tools for detection of disease in early stages.
List of bio markers used in medical diagnosis
Table showing a list of various existing biomarkers archived from Jain, (2017) and Mannino et al., (2014).
Sample type/ Method of detection
|Cancer antigen (bio molecules) based bio markers|
|Prostate-specific antigen (PSA)||Prostate cancer||Serum/ Immunoassay|
|Alpha-foetoprotein (AFP)||Hepatocellular carcinomas (HCC)||Serum/ Immunoassay|
|Cancer antigen 125 (CA125)||Ovarian cancers
Fallopian tube cancer
|Cancer antigen 15-3 (CA15-3)||Breast cancer||Serum/ ELISA,
Lymph node/ IHC,
Bone marrow/ IHC
|Cancer antigen 19-9 (CA 19-9)||Pancreatic cancer
|BRCA-1, BRCA-2||Breast cancer||Tumour samples/ RT-PCR|
|Carcinoembryonic antigen (CEA)||Colorectal cancer||Serum/ ELISA|
|Human chorionic gonadotrophin (hCG)||Germ cell tumours (ovarian and testicular)||Serum/ ELISA|
|Thyroglobulin (Tg)||Papillary and follicular thyroid cancer||Serum/ ELISA or IHC with TPO Ab|
|Heat shock proteins (HSPs)
|Gastric, prostate carcinoma, osteosarcomas, uterine, cervical, and bladder carcinoma||Serum/ ELISA|
|TGFβ||Malignant tumours||Serum / ELISA|
|Metabolic bio marker|
|Glucose metabolism||All cancers, general||Imaging/ FDG-PET scan|
|Genetic bio marker|
|Genetic translocations viz. Philadelphia chromosome, Bcl2 and other gene translocation fusion products||AML, ALL, CML, MDS and Burkitt’s lymphoma||Bone marrow or peripheral blood/ FISH|
squamous cell carcinoma of the stomach, pancreas, thyroid and ovary
|Blood, Tumour sample/ RFLP of chromosome 5q21-22, Methylation status of APC gene|
|Cells as bio marker|
|Circulating tumor cells (CTCs)||Metastatic breast cancer, etc.||Blood/ Immunocytometry|
Thus, this review provides a brief account on various bio markers for diagnosis, prognosis and therapeutic purposes. However, these include markers already in clinical practice as well as various upcoming bio markers. Therefore, future challenges in the bio markers using genomic and proteomic diagnostic technology include the development of complex mathematical algorithms to handle simultaneous analysis of many parameters. However, perhaps up to thousand even to aid the diagnosis instead of a single parameter. Furthermore, issues regarding quality control methods and procedures also require development for using these markers with reliability and reproducible.
- Corella, D. and Ordovs, J. M. (2015) ‘Biomarcadores: Antecedentes, Clasificaci??n y gu??a para su aplicaci??n en epidemiolog??a nutricional’, Nutricion Hospitalaria, 31, pp. 177–188. doi: 10.3305/nh.2015.31.sup3.8765.
- Jain, K. K. (2017) The handbook of biomarkers, The Handbook of Biomarkers. doi: 10.1007/978-1-60761-685-6.
- Karley, D. (2011) ‘Biomarkers: The Future of Medical Science to Detect Cancer’, Journal of Molecular Biomarkers & Diagnosis, 2(5), pp. 1–7. doi: 10.4172/2155-9929.1000118.
- Mannino, D. et al. (2014) ‘Plasma Fibrinogen as a Biomarker for Mortality and Hospitalized Exacerbations in People with COPD’, Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation, 2(1), pp. 23–34. doi: 10.15326/jcopdf.2.1.2014.0138.