Table 6.

Liquid biopsy in digestive system cancers

Cancer	Liquid biomarker	Origin	Tendency	Downstream target	Function	Reference
HCC	miR-221-3p, miR-223-3p, miR-10b5p, miR-21-5p	Plasma exosome	up		Early diagnostic biomarker	108
	LG3BP, PIGR	Serum exosome	up		Early diagnostic biomarker	110
	ECE1, HOXA1, cle11a, AK055957, PFKP, EMX1 methylation	Plasma	up		Early diagnostic biomarker	112
	cfDNA	Plasma	up		Early diagnostic biomarker, Efficacy monitoring biomarker	115
	CTCs	Peripheral blood	up		Early diagnostic biomarker, Tumor recurrence biomarker	114
	Mixed CTCs, Mesenchymal CTCs	Peripheral blood	up		Early diagnostic biomarker, Disease progression biomarker	116
CCA	microRNA-21, microRNA-221	Plasma	up		Early diagnostic biomarker	122
	hTERT, CK19	Peripheral blood	up		Prognostic biomarker	123
	Osteopontin (OPN)	Serum	down	MMP1, MMP10, CXCR4	Efficacy monitoring biomarker, Prognostic biomarker	124
	MMP-7	Serum	up		Early diagnostic biomarker	127
	CYFRA 21-1	Serum	up		Early diagnostic biomarker, Disease progression biomarker	129
	Osteopontin (OPN)	Serum	up		Efficacy monitoring biomarker	130
	CTCs	Peripheral blood	up		Tumor aggressiveness biomarker, Prognostic biomarker	131
	cfDNA mutation	Bile	up		Prognostic biomarker	132
CRC	microRNA-203	Serum exosome	up	M2-TAM	Prognostic biomarker	135
	microRNA-21	Plasma exosome	up		Tumor recurrence biomarker, Prognostic biomarker	137
	miR-17-5p, miR-92a-3p	Serum exosome	up		Early diagnostic biomarker, Disease progression biomarker	138
	miR-25-3p	Serum exosome	up		Tumor aggressiveness biomarker	139
	miR-196b-5p	Serum exosome	up	STAT3	Efficacy monitoring biomarker	147
	miR-301a, miR-23a	Serum exosome	UP		Early diagnostic biomarker	140
	miR-19a	Serum exosome	up		Tumor recurrence biomarker	142
	QSOX1	Serum exosome	down		Early diagnostic biomarker	145
	ctDNA	Plasma	up		Efficacy monitoring biomarker	151
	ctDNA	Plasma	up		Tumor recurrence biomarker, Prognostic biomarker	152