Potential Cancer Biomarkers

Potential Cancer Biomarkers

Any biomolecule or biological processes which may lead to a cancer prognosis, screening, risk assessment or therapy are potential candidates as cancer biomarkers (Mishra, 2010). There is an abnormal expression of specific biomolecules such as peptides, proteins, and nucleic acids in cancer tissues that can be considered as potential candidates for biomarkers. A biomarker can also be a collection of alterations that leads to change in the gene expression or variant protein or metabolic product (Henry, 2012). Types of potential biomarkers may include micro RNAs (miRNAs), circulating long non-coding RNAs (lncRNAs), extracellular vesicle (EV)-associated proteins, circular RNAs (circRNAs), messenger RNAs (mRNAs), enzymes, genetic variants and epigenetic modifications (Fig. 1).

Circulating miRNAs are small, non-coding RNA molecules that can regulate gene expression and may act as potential oncogenes or tumor suppressors. Thus, they are considered as potential biomarkers for cancer screening. Abnormal expression profiles of regulated miRNAs in both tumor paraffin sections and body fluids with high specificity, sensitivity, and stability shows its potential as cancer biomarkers (Matsuzaki, 2017). Moreover, miRNA microarrays and high-throughput techniques are being used in understanding altered miRNA expressions to correlate it with occurrence of human carcinogenesis (Biomarkers Definitions Working Group 2001).

Extracellular vesicles (EV) are small membrane-bound structures that helps in local and distant cell-to-cell communication. Tumor-derived EVs modifies the microenvironment and evades the immune system. Thus, facilitate metastasis and angiogenesis (Matsuzaki, 2017). Micro-RNAs contained within EVs are functionally associated with cancer phenotypes. Understanding the physiological alterations in EVs during tumorigenesis helps to design better therapeutic approach. Considering these factors and their stability in body fluids, investigations are being carried out to elucidate the role of EV-derived miRNAs as tumor biomarkers (Kinoshita, 2017).