Circulating tumor DNA in blood: Future genomic biomarkers for cancer detection

Cancer is characterized by Darwinian evolution and is a primary cause of mortality and morbidity around the globe. Over the preceding decade, the treatment of cancer has been markedly improved by many targeted therapies, but these treatments have given birth to new challenges and issues. Clonal evolution and tumor heterogeneity present a significant challenge in designing cancer therapies. Fortunately, these restrictions have been overcome by technological advancements allowing us to track both genetic and epigenetic aberrations. Cell-free circulating tumor DNA (ctDNA) analysis, or "liquid biopsy" from a blood sample, provides the opportunity to track the genetic landscape of cancerous lesions. This review focuses on ctDNA analysis as a noninvasive method and versatile biomarker for cancer treatment and technological advancements for ctDNA analysis. This method may able to cope with all the challenges associated with previous cancer therapies and has the potential to monitor minimal residual disease, tumor burden, and therapy response and provide rapid detection of relapse. However, there are many challenges that still need to be addressed. Future prognosis, diagnosis, and analysis of ctDNA require reproducibility and accuracy of results, which are not possible without the validation and optimization of procedures. Integrated digital error suppression has thus far shown promise in the detection of ctDNA in cancer.