ctDNA Detection in Microfluidic Platform: A Promising Biomarker for Personalized Cancer Chemotherapy

Table 1

Laboratory methods for ctDNA detection to identify rare mutational marker and the presence of tumor.

Method	Description	Limitations	References
Whole genome sequencing	Deep sequencing of the genome	Expensive, limited to SCNA detection with low insensitivity	[53]
Whole exome sequencing	Deep sequencing of the exome	Expensive and low insensitivity	[53]
Next-generation sequencing	Capture-based deep sequencing for detecting 95% of tumor in NSCLC. Detection specificity of 96% for mutant allele fraction in 100% of stages II-IV patients and 50% of stage I patients	Less comprehensive than whole genome/exome sequencing	[26, 54]
Digital or droplet digital PRC	Detect EGRF mutant in NSCLC with analysis of 81% sensitivity and 85% specificity	Detection limit to a small number of genomic positions in the sample	[24]
	Detect ctDNA and confirm the presence melanoma skin cancer		[48]
	Detect ctDNA and confirm the presence of colorectal cancer		[49]
	Detect ctDNA and confirm the presence of breast cancer		[50]
	Detect rare mutation marker		[52]
PCR	Amplifying rare mutant DNA molecules and detecting allele-specific mutation	Lower sensitivity, detection limit to a small number of genomic positions in the sample	[51]
Modified next-generation sequencing	Digital error suppression-enhanced deep sequencing for 90% of sensitivity, 96% specificity in mutation EGFR kinase domain detection	Less comprehensive than whole genome/exome sequencing	[55]
BEAMing	Evaluate specifically RAS mutation in the blood	Evaluate only known cell mutations	[42]

Note: SCNA: somatic copy number alteration; NSCLC: non-small-cell lung cancer; EGRF: epidermal growth factor receptor; PCR: polymerase chain reaction; BEAMing: beads, emulsions, amplification, and magnetics.