A suggestion for a novel in vitro diagnostic test for endometriosis

A newly developed test shows promising results with high specificity in diagnosing all stages of endometriosis

Key Points

Highlight

• Serum biomarkers CA125 and brain-derived neurotrophic factor (BDNF) when used in combination with some clinical data may show promising results to be used as a novel in vitro diagnostic test for endometriosis.

Importance

• As common as endometriosis is, there is not an established consensus on a non-invasive diagnostic test.
• Using some serum biomarkers in combination with clinical data, it could be possible to help endometriosis patients get diagnosed quickly.

What's done here

• A new in vitro diagnostic test was developed using serum biomarkers CA125 and BDNF along with some clinical variables to be used in diagnosing endometriosis.
• The test was evaluated to validate its performance.
• The serum samples and clinical data were retrieved from the Oxford Endometriosis CaRe Centre biobank. 

Key results

• CA125 and BDNF were able to statistically significantly distinguish all stages of endometriosis cases from controls when used in combination.
• BDNF was elevated in lower stages and CA125 was elevated in higher stages of endometriosis.
• Six clinical variables were detected to significantly distinguish cases from controls.
• The validation study of the test showed a limited sensitivity (46.2%) and a very high specificity (100%).
• The test was also able to identify 32% of the cases with superficial lesions.

Strengths

• All participants underwent laparoscopy to provide the actual clinical state of the patients. 

Lay Summary

As the research continues to find a gold standard non-invasive diagnostic method for endometriosis, there still is no definitive answer. One of the most commonly studied markers is Cancer Antigen 125 (CA125) – a biomarker that is secreted from the derivatives of the embryonic coelomic epithelium which is shown to be significantly increased in the later stages of endometriosis in previous studies. Another is brain-derived neurotrophic factor (BDNF) – a neurotrophin that is shown to be increased in the ectopic endometrial tissue and uterus of women with endometriosis in the earlier stages. 

Herranz Blanco et al. from Spain and Italy conducted two studies aiming to generate a diagnostic method combining these two biomarkers with clinical data for all stages of endometriosis and validate the performance of this diagnostic test. The results of the study were published in the June 2023 issue of the journal Biomolecules. 

Serum samples and clinical data of a total of 204 patients (136 cases, 68 controls) who underwent laparoscopy for suspicion of endometriosis were extracted from the Oxford Endometriosis CaRe Centre biobank. CA125 and BDNF concentrations were determined quantitatively by the ELISA method. Results showed that when used in combination CA125 and BDNF were able to statistically significantly distinguish all stages of endometriosis cases from controls with BDNF being elevated in lower stages and CA125 being elevated in higher stages.

An in vitro diagnostic test was therefore developed using these two serum biomarkers with six clinical variables including the record of previous surgery looking for endometriosis, painful periods as a symptom leading to referral for endometriosis, the severity of menstrual pain during the last cycle, age at first experience of intercourse pain, age at first regular use of painkillers and age at first diagnosis of ovarian cyst which were found to be different between the groups.

Even though the validation study of the test showed a limited sensitivity (46.2%), a very high specificity rate of 100% was achieved. Moreover, the test was able to identify 32% of the cases that presented with peritoneal lesions.

The researchers conclude that this simple-to-use, novel in vitro diagnostic test for endometriosis can be included in the early management of patients along with other clinical symptoms in the accurate and timely diagnosis or exclusion of endometriosis.

Research Source: https://pubmed.ncbi.nlm.nih.gov/37509088/