. 2015 May;17(3):209–224. doi: 10.1016/j.jmoldx.2015.02.001

Table 2.

Review of Evidence-Based Clinical Utility of Analytes

Analyte	Type of DNA/RNA	Clinical utility	Evidence level^∗
CTCs		Burden is prognostic	Level I for metastatic breast⁶⁸ and level II-1 for prostate cancer⁶⁷
Exosomes and circulating microvesicles		Burden is prognostic	Level III⁶⁹
Circulating nucleic acids	cfDNA, ctDNA	Burden is prognostic	Level II-2⁷⁰
	cfRNA	Marker of therapeutic response	Level III⁷¹
	miRNA	Up-regulation is possibly prognostic	Preclinical

Evidence levels are based on those established by the US Preventative Services Task Force and are denoted as follows: level I, evidence obtained from at least one properly designed randomized controlled trial; II-1, evidence obtained from well-designed controlled trials without randomization; II-2, evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group; II-3, evidence obtained from multiple time series designs with or without the intervention (dramatic results in uncontrolled trials might also be regarded as this type of evidence); and III, opinions of respected authorities, on the basis of clinical experience, descriptive studies, or reports of expert committees.

cfDNA, cell-free DNA; cfRNA, cell-free RNA; CTC, circulating tumor cell; ctDNA, circulating tumor DNA.

^∗

Designations of levels of evidence are based on the listed citations and were agreed to by the authors. No other authority provides the basis for these designations.