Table 4.

Most promising cervicovaginal fluid-based EC metabolomic biomarker candidates and their functions.

Metabolite	Group/Sub-Class	Potential Clinical Utility	Biochemical Function and Summary of Evidence
Fumarate [79]	Organic acid (Dicarboxylate)	Diagnosis/early detection	Intermediate in the citric acid cycle. Converted to malate. Citric cycle releases stored energy through the oxidation of acetyl-CoA.
Malate [79]	Dicarboxylic acid	Diagnosis/early detection	Intermediate in the citric acid cycle
Isoleucine [79]	Essential amino acid	Diagnosis	Alpha-amino acid useful in the biosynthesis of proteins. Associated with insulin resistance. Both glucogenic and ketogenic. Reported in serum [87].
Asparagine [79]	Non-essential amino acid	Diagnosis/early detection	Amino donor in urea, pyrimidine and purine synthesis. Supports protein synthesis during glutamine starvation. Reported in serum [87].
Aspartate [79]	Non-essential amino acid	Diagnosis	Involved in protein synthesis and neurotransmission.
Cholines/acylcholines [79]	Conjugated lipids	Diagnosis Prognosis (elevated in Type 2 EC)	Necessary for homocysteine synthesis. Acylcholines enhance penetration of estradiol in tissues. Reported in tissue/serum [78,80].
Phenylalanine [79]	Essential amino acid	Diagnosis Early detection	Precursor for tyrosine, dopamine and norepinephrine. Inhibits proliferation without affecting apoptosis or autophagy. Also reported in plasma [71,92].
Phosphocholine [79,92]	Phospholipid	Diagnosis Prognosis (high-grade EC)	Plays a role in biosynthesis of cell membranes. Surrogate marker for cell proliferation, inhibition of invasion and migration. Protects against TNF-induced apoptosis. Elevated in CVF of EC patients. Also seen in plasma [92].