Table 4.

List of altered metabolite levels identified in plasma/serum samples of BC patients to study several aspects of this pathology.

Metabolite	BC vs. CTR						ER+ vs. ER−	MBC vs. EBC						REL vs. NR		Response to Chemotherapy
																PR vs. GR					Changes during Treatment
	[115]	[98]	[95]	[94]	[111]	[100]	[99]	[97]	[98]	[105]	[108]	[110]	[113]	[105]	[102]	[112]	[106]	[92] (NAC)	[114] (NAC)	[99] (NAC)	[92] (NAC)	[92] (NAC + Bevacizumab)	[107] (Trastuzumab+ Everolimus)
3-hydroxy-2-Methyl-butanoic acid															↓
3-Hydroxybutyrate										↑	↑				↓							↑
Acetate										↑							↓				↓↑↑		↓
Acetoacetate	↑										↑										↓↑↓	↑	↓
Acetone	↓		↓																				↑
Alanine	↓			↑	↑					↑	↓												↓
Albumin Lysyl																							↓
Apo-B							↑													↑
Arginine		↑	↑
Betaine											↓												↓
Cholesterol							↑													↑
Choline										↑				↑	↓								↓
Citrate	↑																	↑			↓↓↓		↓
Creatine			↑							↑											↓↑↑		↓
Creatinine			↑				↑			↑											↓↑↑		↓
Dimethylglutarate																					↑↓↑
Ethanol						↑														↑
Formate		↓								↑					↓		↓				↓↓↓	↓
Glucose	↑	↑	↑		↓			↑		↓		↑	↑			↓							↓
Glutamate	↓	↑			↑				↑	↑	↑			↑	↓	↑
Glutamine	↑	↓	↑					↓		↓									↑
Glycerol						↑					↑
Glycerol-derived compounds			↓																				↑
Glycerophosphocholine																							↓
Glycine		↓							↓	↑				↑							↑↑↓
Glycoproteins			↓
Histidine						↑				↑	↓		↓	↑	↓			↓	↓		↓↑↑		↓
Isoleucine		↓								↑				↑					↓	↑	↑↓↓		↓
Lactate	↓	↑		↑	↑			↓	↑	↑			↑	↑	↑						↑↓↓
Leucine										↑				↑							↑↓↑	↑
Linolenic acid																			↑
Lipids		↑	↓	↑	↑						↑	↓	↑										↑
Lipoproteins		↑	↓																				↑
Lysine		↑	↑		↑			↓				↑									↑↓↑		↓
Mannose											↑												↑
Methanol																							↓
Methionine										↑											↓↑↑
Myo-Inositol																							↓
N-acetyl glycoproteins		↑			↓	↑			↑		↑												↑
N-Acetyl-Cysteine												↑
N-Acetyl-Glycine															↓
Nonanedioic acid															↓
Ornitine																					↓↑↑
Phenylalanine										↑	↑	↑		↑		↑		↓			↓↑↑		↓
Phospholipids							↑													↑
Proline										↑		↑			↓								↓
Pyruvate					↓			↓			↑										↓↓↑
Threonine																			↑
Triglycerides																				↑
Tyrosine	↓	↑								↑			↑	↑	↑								↓
Unsaturated lipids			↓
Valine		↓	↑	↑										↑						↑	↓↑↑		↓

BC: breast cancer; CTR: control; ER: estrogen receptor; PR: poor responders; GR: good responders; NAC: neoadjuvant chemotherapy; MBC: metastatic BC; EBC: early BC; REL: relapse; NR: no relapse. ↑/↓ higher/lower level in the first group of each comparison.