Oral Cancer Biomarkers: Is it a Meaningless Game?

Abstract

There are forever new biomarkers discovered every now and then, claiming for their clinical diagnostic and prognostic potentials. When is it going to end or would it ever ends at all? During the preomics era, it used to be only a handful of protein markers with well-studied in-depth mechanism of actions. Then came an explosive big data era: genomics, transcriptomics, proteomics, epigenomics, metabolomics, etc., generating huge amount of biomolecular data beyond researchers’ ability to handle let alone understand their significance in health and disease.1,2 It was akin to a child walking into a candy shop overwhelmed by the choices. Researchers are currently busy trying to make sense of these data and slowly attempting to translate them into clinical benefits.2 Just within the field of oral cancer, omics data are being generated from all sorts of host samples types, including saliva, buccal swaps, tissue biopsies, serum, plasma, lymphatic fluids, etc. Within each sample type, one has choices of investigating Deoxyribonucleic acid (DNA), Ribonucleic acid (RNA), protein, metabolites, small molecules, etc, originating from various cellular compartments such as nuclei, cytoplasm, membranes, mitochondria, microvesicles (exosomes),3 extracellular fluids (serum, plasma, lymphatic fluids, etc) and etc. Disease and healthy samples are being compared in the aim to identify key driver ‘cancer biomarkers’ with clinical potentials. As cancer is now perceived as a disease due to ‘molecular reprogramming’,4 hence, biomarker researchers are trying to identify
global molecular events that induce normal cell to reprogram itself into cancer. Given the complexity and heterogeneity of cancers, predictably, huge numbers of molecular differences exist between normal and cancer samples, and can vary from individual to individual.