Evolving utility of exosomes in pancreatic cancer management

Table 2 Comparison of usefulness of various liquid biopsies in pancreatic cancer

Item	CTC[20-22]	Ct DNA[21,23,24]	Exosomes[20,25-28]	CA 19-9[20,21,28-30]
Origin	Viable tumor cells	cfDNA, viable tumor cells, CTCs	DNA, proteins, lipids, RNAs metabolites, and tumor cells	Ductal cells in the pancreas, biliary system, and epithelial cells in the stomach, colon, uterus, and salivary glands
Samples used	Plasma	Frozen plasma, urine and other biofluids	Frozen plasma, urine and other biofluids	Plasma
Methods	CellSearch, MACS, Dynabeads, microfluidic, SE-iFISH, CD45/CEP8/DAPI staining-FISH, anti-EpCAM Portal-vein blood	Real-time quantitative PCR, digital PCR, droplet digital PCR, next-generation sequencing; commercial liquid biopsy platforms: GuardantTM (breast, colon, and lung cancers and multi-cancer detection) FoundationOne® (multi-cancer detection); signateraTM (colorectal cancer), Galleri (multi-cancer detection), CancerSEEK (multi-cancer detection), TempusTM (multi-cancer detection), Caris (bioinformatics testing of both circulating DNA and RNA)	Ultracentrifugation, ExoChip, precipitation, size-based isolation immunoaffinity-based isolation microfluidics-based isolation	Radio immuno assay
Mutation analysis	Yes	Yes	Yes	No
Drug delivery vehicle	No	No	Yes	No
Sensitivity	76.0%	65.0%	50.0%-85.0%	78.2%
Specificity	68.0%	75.0%	90.0%	82.8%
Usage in clinics	Diagnosis of PDAC, prognosis/prediction of PDAC	Diagnosis of PDAC; monitoring treatment efficacy; monitoring of disease progression	Diagnosis and prognosis of PDAC; prognosis/prediction of PDAC	Combining ct DNA with CA 19-9 levels could improve diagnostic sensitivity to 98%, and specificity to 97%; monitoring treatment efficacy; monitoring of disease progression

PDAC: Pancreatic ductal adenocarcinoma; CTC: Circulating tumour cells; CA: Carbohydrate antigen; ctDNA: Circulating tumor DNA.