Identification of candidate microRNA biomarkers of endometriosis in different bodily fluids

Why this matters for women’s health

Endometriosis is a painful and often disabling condition that affects up to one in ten women of reproductive age, yet it typically takes years to diagnose because confirmation still relies on surgery. This study explores whether tiny molecules called microRNAs, circulating in easily collected bodily fluids like blood, saliva, and vaginal mucus, could serve as simple, noninvasive clues that a woman has endometriosis—potentially shortening the long and frustrating journey to diagnosis.

Hunting for clues in everyday fluids

To look for these molecular clues, researchers collected blood serum, saliva, and vaginal mucus from 20 women scheduled for gynecologic surgery—10 with moderate to severe endometriosis and 10 with other benign conditions. Using next-generation sequencing, they measured thousands of microRNAs, short RNA fragments that help control how genes are turned on and off and that have already been linked to cancer, infections, and autoimmune diseases. By comparing patients and controls across these three fluids, the team aimed to see not only whether any microRNAs differed, but also whether some fluids were richer, more informative sources than others.

Different fluids, different molecular fingerprints

The analysis showed that each fluid carried its own distinct microRNA “fingerprint.” Serum contained the richest collection, while saliva had the fewest detectable microRNAs. In total, the researchers found 13 microRNAs that differed between women with and without endometriosis in serum, 3 in saliva, and 6 in vaginal mucus. Surprisingly, there was no single microRNA that changed in all three fluids, and only one overlapped between serum and vaginal mucus. This suggests that each fluid reflects different aspects of the body’s response to the disease, shaped by where it comes from and which tissues feed into it. Notably, vaginal mucus—routinely collected during pelvic exams—held more microRNAs than saliva, highlighting it as an underused but practical sample type for future testing.

Linking tiny RNAs to bigger biological changes

Finding different microRNAs is only useful if they point to meaningful biological changes. To explore this, the team predicted which genes these altered microRNAs might control and then looked at which cellular processes those genes participate in. Across the fluids, the target genes clustered in pathways involved in cell death, tissue remodeling, cell aging, and the Wnt and TGF-beta signaling systems—networks already suspected in the growth and survival of endometriotic lesions. To strengthen the picture, the researchers also measured proteins in serum and overlaid those data with the microRNA findings. They identified 59 proteins that were increased in women with endometriosis and also likely controlled by the dysregulated microRNAs, including several proteins connected to cell growth, inflammation, and tissue scarring.

Candidate markers for a future blood test

Among the many microRNAs flagged in serum, two members of the same family—miR-200a-3p and miR-200b-3p—stood out. When the team measured these by a more targeted method (qPCR), the results suggested that each offers modest ability to distinguish women with endometriosis from those without, though not yet strong enough to be used alone as a definitive test. The study also uncovered several other, previously unreported microRNAs with potential roles in inflammation, fibrosis, and abnormal tissue growth in endometriosis. Because the study was small and focused on women with more advanced disease, the authors stress that these signals are preliminary and require confirmation in larger, more diverse groups and across different stages of the condition.

What this means going forward

For patients and clinicians, the key message is that a simple, reliable blood or mucus-based test for endometriosis is not available yet—but research is moving in that direction. This study shows that microRNAs in easily collected fluids capture important aspects of the disease’s biology and can be integrated with protein measurements to highlight promising biomarker candidates. If future, larger studies confirm and refine these findings, they could ultimately lead to noninvasive tests that help diagnose endometriosis earlier, monitor how it responds to treatment, and reduce the need for diagnostic surgery.

Citation: Lyu, S., Li, Q., Gu, Z. et al. Identification of candidate microRNA biomarkers of endometriosis in different bodily fluids. Sci Rep 16, 6218 (2026). https://doi.org/10.1038/s41598-026-37277-5

Keywords: endometriosis diagnosis, microRNA biomarkers, noninvasive testing, womens reproductive health, vaginal mucus and saliva