Can plasma microRNAs be used as a non-invasive diagnostic test for the detection of endometriosis?

Plasma miR-17-5p, miR-20a and miR-22 are down-regulated in women with endometriosis compared with those without endometriosis in mainland China.

There is currently a pressing need to develop a non-invasive diagnostic test for endometriosis. Altered circulating microRNA profiles have already been linked to various disease states.

This was a prospective laboratory study in a tertiary-referral university hospital in Beijing, PR China, between January 2012 and May 2012. Twenty-three women with histologically proven endometriosis and 23 endometriosis-free controls were enrolled in this study.

Laparoscopic inspection of the abdominopelvic cavity was performed for each patient, and peripheral blood samples were collected before laparoscopy. Microarray-based microRNA expression profiling was used to identify differentially expressed microRNAs in plasma samples between women with and without endometriosis, and quantification of selected microRNAs was performed using quantitative RT–PCR.

Twenty-seven microRNAs were differentially expressed between women with and without endometriosis, of which six microRNAs (miR-15b-5p, miR-17-5p, miR-20a, miR-21, miR-22 and miR-26a) were selected for validation. MiR-17-5p, miR-20a and miR-22 were significantly down-regulated in women with endometriosis compared with controls (P = 0.011, 0.0020 and 0.0002, respectively), yielding an area under the receiver operator characteristics curve of 0.74 [95% confidence interval (CI): 0.58–0.90], 0.79 (95% CI: 0.65–0.93) and 0.85 (95% CI: 0.71–0.98) in discriminating endometriosis from controls, respectively.

Our sample size was small and all cases were rAFS stage III–IV, which may limit generalization of plasma microRNAs for early diagnosis of endometriosis. Moreover, only six microRNAs were selected for validation.

Plasma microRNAs provide a promising opportunity for detection of endometriosis.

This research was supported by the National Natural Science Foundation of China (81170548) and Key Project for Clinical Faculty Foundation, Ministry of Health, China (2010). All authors declare no conflict of interest.