Table 1.

Metabolomic Studies Performed in Urines from PCa Patients

PCa Subject Group	Control Group	Analytical Platform	Statistical Methods	Total Metabolites Found/Discriminative Metabolites Found	Discriminatory Metabolites/Biomarkers	Metabolic Pathways Dysregulated	Ref.
n= 13	n= 24	GS-MS	Binary strings, Similarity coefficients	91/21	Butyrolactone, methyl vinyl ketone, methylamine, N-ethylformamide, acetonitrile dimethylamino, pyridine, N-methyl-formamide, acetaldehyde, acetamide, 1-methyl-piperidine, 1-piperidineacetonitrile, dimethylamine, pyrrole, methacrolein, N-N-dimethylamine, 3-methyl-pyridine, 2-methyl-1H-pyrrole, 2-octanone, 1-ethyl-1H-pyrrole, 2-n-butylacrolein and methyl propyl disulfide	NS	[65]
n= 59	n= 51	LC-MS GS-MS	Wilcoxon P test, hierarchical clustering, nonparametric tests	583/34	Sarcosine (+)	Alterations in glycine synthesis and degradation	[53]
n= 106	n= 57 (33 patients with no evidence of malignancy plus 24 HC)	GC-MS	Nonparametric statistical tests and ROC	NS/0	No relevant differences in sarcosine levels between patients with and without PCa		[61]
n= 3	n= 5	LC-MS	NS	NS/5	1.Sarcosine 2.Proline 3.Kynurenine (+) 4.Uracil (+) 5.Glycerol 3-phosphate (+)	1. Alterations in glycine synthesis and degradation Sarcosine is an intermediate compound in the metabolism of choline. 2. Alteration in amino acids metabolism 3. Alteration in kynurenine pathway 4. Alteration in pyrimidine metabolism 5. Alteration in energetic metabolism	[55]
n= 25 PCa patients developing biochemical recurrence	n= 29 PCa patients who remained recurrence-free	GC-MS	ROC	8/2	Sarcosine (+) Cysteine (+) (in the group developing biochemical recurrence)	Alterations in glycine synthesis and degradation	[56]
n= 33	n= 23 (13 HC plus 10 patients with BPH)	GC-MS	Nonparametric statistical tests and ROC	NS/1	Sarcosine (+)	Alterations in glycine synthesis and degradation	[57]
n= 86	n= 45	LC-MS	ROC	NS/1	Diagnostic value of sarcosine was modest; relationship with clinicopathologic parameters was not found	Alterations in glycine synthesis and degradation	[58]
n= 20	n= 28 (8 patients with BPH plus 20 HC)	GC-MS	PCA ROC	81/5	Dihydroxybutanoic acid (+), xylonic acid (+), pyrimidine (−), ribofuranoside(−), and xylopyranose(−)	Alterations in carbohydrate and energy metabolism	[60]
n= 211	n= 134	GC-MS	ROC	NS/1	Sarcosine (+)	Alterations in glycine synthesis and degradation Sarcosine is an intermediate compound in the metabolism of choline.	[59]
n= 32	n= 32	LC-MS GC-MS	PCA PLS-DA	1132/15	1. Glycine (−), serine(−), threonine (−), alanine (−) 2. Glutamine (−), citrate (−), aconitate (−), succinate (−) 3. Sucrose (−), sorbose (−), arabinose (−), arabitol (−), inositol (−), galactaric acid (−) 4.Carnitines (−)	1. Alteration in amino acids metabolism 2. Disturbance in energy metabolism 3. Dysregulation in carbohydrates degradation 4. Alteration in long-chain fatty acids metabolism	[63]
n= 59	n= 43	GC-MS	RF LDA	196/4	1. 2,6-dimethyl-7-octen-2-ol (−), 3-octanone (−), 2-octanone (−) 2. Pentanal (+)	1. Increase of utilization of these metabolites for increased energy consumption 2. Inflammatory conditions via the excessive production of reactive oxygen species, known to induce lipid peroxidation	[64]

BPH, benign prostatic hypertrophy; GS-MS, Gas chromatography–mass spectrometry; HC, healthy controls; LDA, linear discriminant analysis; LC-MS, Liquid chromatography–mass spectrometry; NS, not specified; PCA, Principal component analysis; PLS-DA,Partial least squares discriminant analysis RF, random forest; ROC, receiver-operator characteristic.

(+): levels increased in PCa; (−): levels decreased in PCa.