Urinary peptide profiling identifies a panel of putative biomarkers for diagnosing and staging endometriosis

Objective: To identify a potential diagnostic endometriosis marker using matrix-enhanced laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based urinary proteomics.

Design: Prospective randomized pilot study.

Setting: University hospital, tertiary referral center for endometriosis.

Patient(s): 53 women undergoing laparoscopic surgery for pain and/or infertility comprising 30 women without endometriosis and 23 with endometriosis.

Intervention(s): Laparoscopy and urine specimens.

Main outcome measure(s): Urinary peptide profiles.

Result(s): We observed distinct patterns of peptide profiles in the urine samples of women presenting with typical clinical symptoms of endometriosis. Six statistically significant putative peptide markers were identified (four during the periovulatory phase and two during the luteal phase) by comparing controls with moderate/severe endometriosis patients. The periovulatory peptide mass of 1,767.1 Da and the luteal peptide mass of 1,824.3 Da both showed a sensitivity of 75% and a specificity of 85% and 71%, respectively. Also detected were seven peptide markers (two during the periovulatory phase and five during the luteal phase) by comparing the urinary peptide profiles of patients with minimal/mild to moderate/severe endometriosis. The periovulatory peptide mass of 3,280.9 Da and the luteal peptide mass of 1,933.8 Da showed a sensitivity of 82% and 75% and a specificity of 88% and 75%, respectively.

Conclusion(s): Urinary proteomic analysis may provide a novel method of diagnosing and staging endometriosis.