Table 2. Advantages and disadvantages of clinical diagnostics with FFPE and blood ctDNA detection.

Sample type	FFPE	Blood/ctDNA
Reliable variation types detected by NGS	SNV; indel; CNV; fusion	SNV; indel; fusion
Sensitivity	Moderate, variation with 1% mutant allele frequency	High, variation with 0.1% mutant allele frequency
Cost	Moderate	High
Sample collection	Difficult	Easy
Genes numbers	Multi-gene panel or with 400–500 genes	Multi-gene panel with less than 100 genes, or amplicon panels
Cancer types and stages	All solid tumors and select hematologic malignancies. All stages	Advanced cancers (stage IIIB to IV) with select cancer types such as lung, breast or colon cancer

FFPE, formalin fixed paraffin embedded; ctDNA, circulating tumor DNA; NGS, next generation sequencing; SNV, single nucleotide variation; indel, short insertion/deletion; CNV, copy number variation.