Circulating microRNAs as potential biomarkers for endometriosis

Abstract

OBJECTIVE: To evaluate whether microRNAs (miRNAs) associated with endometriosis are detectable in the circulation and could serve as potential noninvasive biomarkers for endometriosis.

DESIGN: Case-control study.

SETTING: University hospital.

PATIENT(S): Twenty-four women with endometriosis and 24 women without the disease (controls).

INTERVENTION(S): Serum samples collected from women undergoing laparoscopy for endometriosis and other benign gynecologic disease.

MAIN OUTCOME MEASURE(S): Total RNA extracted from serum and quantitative reverse-transcription polymerase chain reaction to determine levels of miRNA let-7a-f and miR-135a,b.

RESULT(S): The levels of circulating let-7b and miR-135a were statistically significantly decreased in women with endometriosis compared with controls, and let-7d and 7f showed a trend toward down-regulation. Let-7b expression strongly correlated with serum CA-125 levels and showed the highest area under the curve of 0.691. When the patients were analyzed according to phase of the menstrual cycle, the expression of let-7b, 7c, 7d, and 7e was statistically significantly lower in the women with endometriosis during the proliferative phase. Using a logistic regression model, we evaluated the diagnostic power of differently expressed miRNAs; the combination of let-7b, let-7d, and let-7f during the proliferative phase yielded the highest area under the curve value of 0.929 in discriminating endometriosis from controls.

CONCLUSION(S): Several circulating miRNAs are differentially expressed in the sera of women with endometriosis compared with controls. The combination of serum let-7b, 7d, and 7f levels during the proliferative phase may serve as a diagnostic marker for endometriosis.