Proteomic Analysis of Cervicovaginal Fluid for Diagnostic Endometriosis Biomarker Discovery.

PURPOSE: Endometriosis is a prevalent inflammatory condition characterised by the presence of endometrial-like tissue outside the uterus and is associated with significant challenges, including diagnostic delays and continued reliance on laparoscopy. Although extensive research has investigated potential biomarkers in various biofluids, none have been validated for clinical use. EXPERIMENTAL DESIGN: This pilot study explored the proteome of cervicovaginal fluid to identify biomarkers of endometriosis. SWATH-MS was performed over two experiments on cervicovaginal fluid sampled via a low vaginal swab, from people with (n = 20) and without (n = 19) surgically confirmed endometriosis. STRING, OPLS-DA modelling and ingenuity pathway analysis were used to interrogate the data. ELISA was performed validate SWATH-MS findings. RESULTS: There were 29 proteins in experiment one and 47 proteins in experiment two identified as differentially abundant between cases and controls. No proteins were identified as differentially abundant in both experiments. Legumain (LGMN) measured via ELISA was significantly increased in the cervicovaginal fluid of people with endometriosis. CONCLUSIONS AND CLINICAL RELEVANCE: Cervicovaginal fluid proteins sampled via vaginal swab may have limited biomarker potential for endometriosis. A larger and more diverse cohort would be required to confirm the promise of cervicovaginal fluid LGMN as a candidate biomarker of endometriosis.