Table 1.

Noninvasive biomarkers.

Indicator Type	Biomarker	References
Tissue damage	Faecal haemoglobin	[7,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51]
Inflammation	Calprotectin	[21,23,30,33,34,35,36,37,38,39,40,41,42]
	Chitinase 3-like 1	[43,44,45,46,47,48,49,50,51]
Intercellular stability	E-cadherin	[53,54,55,56,57,58,59,60,61,62,63,64,65,66]
Metabolic	M2-pyruvate kinase	[38,69,70,71,72,73,74,75,76,77,78,79,80,81]
	Volatile organic compounds	[14,23,82,83,84,85,86,87,88,89,90,91,92,93,94]
	Small metabolites	[14,95,96,97,98,99,100]
Host genetics	Genetic and/or epigenetic markers	[102,103,104]
	MicroRNA	[14,105,106,107]
Gut microbiota	Fusobacterium nucleatum	[120,121,122,123,124,125,126]