Emerging Biomarkers in Cancer from Discovery to Clinical Applications

A cancer biomarker specifically identifies characteristics of cancer, ideally with a high degree of accuracy and reliability, reported as its sensitivity and specificity. Biomarkers play an increasingly important role in clinical management with the emergence of biomarkers in cancer diagnosis and selective molecular targeted therapies. Spanning genomics, proteomics, metabolomics, and epigenetics, are providing unprecedented insights into tumor biology and advancing precision medicine. The advanced analytical techniques used in cancer diagnosis include immunohistochemistry, enzyme-linked immunosorbent assay, flow cytometry, fluorescent probe, biosensor, polymerase chain reaction, next-generation sequencing (NGS), liquid biopsy, and bioinformatics, etc. They play a crucial role in the discovery, validation, and clinical application of tumor biomarkers, contributing to improved cancer diagnosis, prognosis, and treatment outcomes. Food and Drug Administration-approved cancer biomarkers, including AFP (Alpha-fetoprotein), Epidermal Growth Factor Receptor (EGFR) mutations, BCR-ABL fusion gene, human epidermal growth factor receptor 2, etc., and CA 19-9 are in clinical trials with respect to their specificity and sensitivity. This chapter explores the journey of cancer biomarkers from discovery to clinical application, emphasizing key technological advancements, bioinformatics tools and validation strategies that underpin their development. Recent advances in next-generation sequencing (NGS) and multiomics approaches have accelerated the discovery of biomarkers, enabling the characterization of tumor heterogeneity and microenvironment dynamics.