Microbial markers in colorectal cancer detection and/or prognosis

Table 1 Fecal metabolic profiling studies in colorectal cancer

Matrix	Cohort	Study observations	Analytical method	Ref.
Aqueous dispersion of stools	111 CRC, 412 healthy controls	Potential to detect colorectal neoplasia	One-dimensional 1H magnetic resonance spectroscopy	[205]
Fecal water extract	21 CRC 11 healthy controls	Reproducible and effective method for detecting colorectal cancer markers. (↘) SCFA (acetate, butyrate) appears to be the most effective marker in CRC.	NMR	[206]
Lyophilized human faeces	11 CRC 10 healthy controls	(↘) butyric acid, linoleic acid, glycerol, (↘) secondary bile acid associated with (↘) Ruminococcus spp., (↗) leucine, valine, acetic acid, valeric acid, isobutyric acid, isovaleric acid, (↗) A. muciniphila associated with (↗) proline, serine, threonine	GC-MS	[193]
Lyophilized human faeces	11 CRC, 10 healthy controls	(↘) fructose, linoleic acid, and nicotinic acid in CRC stools.	GC/TOF-MS	[208]
Volatile organic compounds in the headspace of lyophilized stool samples	40 CRC, 60 advanced adenomas, 57 healthy controls	Discrimination of fecal VOC profiles of patients with adenomas and CRC.	Electronic nose	[209]
Lyophilized human faeces	48 CRC, 102 healthy controls	41 metabolites significantly associated with CRC (↘) xenobiotics (↘) heme, peptides/amino acids, vitamins, co-factors, other CRC associated molecules.	HPLC-GC/MS-MS	[207]
Human faeces	31 CRC, 31 controls with positive FOBT	Discrimination of CRC samples with better specificity and sensitivity than FOBT. (↘) ammonia, sulfides, acetaldehyde	SIFT-MS	[210]
Lyophilized human faeces	42 CRC, 89 healthy controls	Microbe-metabolite correlation in CRC: (↗) Clostridia, Lachnospiraceae, p-aminobenzoate and conjugated linoleate. (↗) Fusobacterium, Porphyromonas, p-hydroxy-benzaldehyde, and palmitoyl-sphingomyelin.	HPLC-GC/MS-MS	[211]
Human faeces	13 CRC	Discrimination of CRC samples with 7 metabolites: alphahydroxyisovalerate, isovalerate, N1-methyl-2-pyridine-5-carboxamide, 7-ketodeoxycholate, deoxycholate, valerate, and tryptophylglycine	UPLC-MS/MS; GC/MS	[165]

CRC: Colorectal cancer; CT: Computed tomography; gFOBT: Guaiac fecal occult blood test; NMR: Nuclear magnetic resonance; MS: Mass spectrometry; GC-MS: Gas chromatography coupled with MS; LC-MS: Liquid chromatography coupled with MS; UPLC: Ultra-performance liquid chromatography; HPLC: High-performance liquid chromatography; TOF: Time of flight; VOC: Volatile organic compounds; SIFT-MS: Selected ion flow tube MS.