title: Digital PCR analysis of circulating nucleic acids.
abstract: Detection of plasma circulating nucleic acids (CNAs) requires the use of extremely sensitive and precise methods. The commonly used quantitative real-time polymerase chain reaction (PCR) poses certain technical limitations in relation to the precise measurement of CNAs whereas the costs of massively parallel sequencing are still relatively high. Digital PCR (dPCR) now represents an affordable and powerful single molecule counting strategy to detect minute amounts of genetic material with performance surpassing many quantitative methods. Microfluidic (chip) and emulsion (droplet)-based technologies have already been integrated into platforms offering hundreds to millions of nanoliter- or even picoliter-scale reaction partitions. The compelling observations reported in the field of cancer research, prenatal testing, transplantation medicine and virology support translation of this technology into routine use. Extremely sensitive plasma detection of rare mutations originating from tumor or placental cells among a large background of homologous sequences facilitates unraveling of the early stages of cancer or the detection of fetal mutations. Digital measurement of quantitative changes in plasma CNAs associated with cancer or graft rejection provides valuable information on the monitoring of disease burden or the recipient's immune response and subsequent therapy treatment. Furthermore, careful quantitative assessment of the viral load offers great value for effective monitoring of antiviral therapy for immunosuppressed or transplant patients. The present review describes the inherent features of dPCR that make it exceptionally robust in precise and sensitive quantification of CNAs. Moreover, I provide an insight into the types of potential clinical applications that have been developed by researchers to date.
authors.affiliation: Centre for Research into Circulating Fetal Nucleic Acids, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China; Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China. Electronic address: irena.hudecova@cuhk.edu.hk.
authors.forename: Irena
authors.initials: I
authors.lastname: Hudecova
mesh_terms: D015415:Biomarkers / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D004247:DNA / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D003936:Diagnosis, Computer-Assisted / Q000639:trends; D005260:Female; D005820:Genetic Testing / Q000639:trends; D006801:Humans; D008297:Male; D025202:Molecular Diagnostic Techniques / Q000639:trends; D010949:Plasma / Q000737:chemistry; D057285:Precision Medicine / Q000009:adverse effects / Q000639:trends; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000009:adverse effects / Q000639:trends; D012313:RNA / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D012313:RNA; D004247:DNA
keywords: Digital PCR; Noninvasive cancer biomarker; Noninvasive prenatal diagnosis; Precision; Sensitivity; Transplantation medicine; Virology