Table 2.

Exosomes as Diagnostic and Prognostic Biomarkers for EC

Cargo Type	Exosomal Cargo	Biofluids	Extraction Method	Identification Method	Detection Method	Clinical Value	Reference
miRNA	miR-652-5p	Serum	Differential centrifugation	Flow cytometry	qRT-PCR	Reduced expression in EC patients	[66]
	miR-21	Serum	Commercial kit	Not shown	qRT-PCR	Related to lymphatic metastasis and stage	[67]
	miR-766-3p	Serum	Commercial kit	TEM and Western blot	miRNA profiling, qRTPCR	Indicator for poor prognosis	[68]
	miR-182	Serum	Commercial kit	Not shown	qRT-PCR	Indicator for poor prognosis	[69]
	miR-340-5p	Plasma	Differential centrifugation	TEM, NTA and Western blot	qRT-PCR	Indicator for radioresistance and poor prognosis	[57]
	miR-339-5p	Serum	Differential centrifugation	TEM and Western blot	qRT-PCR	Predicts response to preoperative radiotherapy	[58]
lncRNA	PCAT1	Serum	Ultracentrifugation	TEM and NTA	qRT-PCR	Higher expression in EC patients	[21]
	UCA1	Plasma	Ultracentrifugation	TEM, NTA and Western blot	qRT-PCR	Biomarker for diagnosis of EC	[73]
	UCA1, POU3F3, ESCCAL-1 and PEG10	Serum	Commercial kit	TEM, NTA and Western blot	qRT-PCR	Biomarker for diagnosis of EC	[74]
circRNA	circ-0026611	Serum	Commercial kit	TEM and Western blot	circRNA microarray, qRT-PCR	Related to lymphatic metastasis and stage	[77]
Protein	Stathmin-1	Serum	Ultracentrifugation	TEM, NTA and Western blot	ELISA	Indicator for poor prognosis	[79]
RNA	seG-chiRNA	Salivary	Commercial kit	TEM, NTA and Western blot	qRT-PCR	Predicts recurrence and therapeutic response of EC	[82]

Abbreviations: EC, esophageal cancer; ELISA, enzyme-linked immunosorbent assay; NTA, nanoparticle tracking analysis; qRT-PCR, quantitative real time polymerase chain reaction; TEM, transmission electron microscope.