Development of cancer diagnostics—from biomarkers to clinical tests

The advent of molecular technologies has revealed a wealth of information about signaling pathways and gene regulation in cancer. New biomarkers and methods for classification of cancer subtypes, diagnosis, prognosis and prediction of response to therapy have been emerging. Advancements in analytical methods in molecular biology, such as polymerase chain reaction (PCR), deoxyribonucleic acid (DNA) arrays and next-generation sequencing have allowed researchers to interrogate a vast type of biological and clinical materials such as formalin-fixed, paraffin-embedded (FFPE) tissue, biopsies and cells present in blood, bone marrow or urine (1-8). Insights gained from the role and significance of the biomarkers in tumor tissues and cells will aid in understanding tumorigenesis and metastasis processes. In addition, the recent finding that circulating tumor cells (CTCs) and circulating DNA in blood can also have diagnostic value in metastatic cancers allowing clinicians to use them as surrogate endpoints (9,10). Diagnostic tests based on such information should enable “real time” biopsies of cancer progression and response to therapy. These new molecular and cellular technologies will enable more precise and objective decision-making