dPCR application in liquid biopsies: divide and conquer

Abstract

Precision medicine is already a reality in the field of oncology given that the selection and use of biomarker-driven therapies has clearly improved patient survival. Furthermore, a new, minimally invasive strategy termed ‘liquid biopsy’ (LB) has revolutionized the field by allowing comprehensive cancer genomic profiling through the analysis of circulating tumor DNA (ctDNA) released into the bloodstream. However, its detection requires extremely sensitive and efficient technologies. A powerful molecular tool based on the principle of ‘divide and conquer’ has emerged to solve this problem. Thus, digital PCR (dPCR) allows absolute and accurate quantification of target molecules. : In this review we will discuss the fundamentals of dPCR and the most common approaches used for partition of samples and quantification. The advantages and limitations of dPCR will be mentioned in the context of the field of LB in oncology. In our opinion, dPCR has proven to be one of the most sensitive methods available for LB analysis, even though some aspects such as its capacity of multiplexing and protocol standardization still require further improvements. Furthermore, the increasing sensitivities and lower costs of next generation sequencing (NGS) methods position dPCR as a confirmatory and complementary technique for NGS results which will likely prove very useful for treatment monitoring and assessing minimal residual disease.