Blood‐Based Biomarkers for the Diagnosis and Prognosis of Cancer

Human blood consists of several essential components, including both cellular and molecular substances which impart information about the healthiness of an individual. A non-invasive measure which is beneficial in the detection of cancer comes from a thorough study of the components of the blood of an individual. The day-to-day upsurge in the cancer mortality rate is creating an urgency in the development of multiple non-invasive strategies for cancer prognosis and diagnosis. Earlier there were only a limited number of cancer screening tests, thus the idea of biomarkers as cancer detection tool started gaining importance due to their efficient, non-invasive, early prediction of cancer, thereby enhancing the opportunity for implementation of therapeutics in combating cancer. The blood-based biomarkers, or “liquid biopsy,” are quite effective in understanding the basic molecular reprogramming that occurs due to tumorigenesis by detailing the alterations that appeared in the whole genome, transcript level, protein level, and the metabolome of the tumor cells/stromal cells. Some of these changed parameters may enter the bodily fluids, essentially the blood. The biomarkers that circulate in the blood which are primarily studied include the circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and exosomes. The liquid biopsy approach has targeted the screening of multi-organ tumors, and this could be a transformational step which might effectively bridge the gap in controlling cancer. Therefore, the biomarkers predict multiple tumors in various sites solely based upon the liquid medium, blood (both serum and plasma) specifying its particular site. There is still a great deal of room for better understanding of the biomarkers found in the blood to become more clinically significant. Therefore, new techniques need to emerge for the improvement of potential early screening and prognosis of cancers. Many obstacles present today in liquid biopsies need to be removed to improve the accuracy of the prediction.