Background: Ovarian cancer is an insidious disease that has few specific symptoms in the early stages and most women with this disease present with an advanced stage at the time of diagnosis. MicroRNAs (miRs) are a class of small noncoding RNAs whose expression changes have been associated with cancer development and progression.

Aim : The objective of this trial was to validate whether serum microRNA-21 can be used as a biomarker for the detection of ovarian carcinoma in patients with a pelvic mass. 

 Methods: Serum samples were obtained preoperatively from women undergoing for an adnexal mass. We measured the levels of microRNA-21 in serum samples from patients with a pelvic mass and healthy controls using real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR). CA125 concentrations were determined in serum samples by ELISA analysis.

Results:  Mean serum concentration of microRNA-21 was significantly higher in serum samples of patients with ovarian cancer (p < 0.01) but not with ovarian endometriomas or other types of benign tumors as compared with healthy controls. As a single marker, microRNA-21 had the highest sensitivity at 68 %. The serum CA125 concentration were elevated in patients with ovarian cancer and ovarian endometriomas. Comparatively, combined microRNA-21 and CA125 yielded the highest sensitivity 73 %.

Conclusions: As a single tumor marker, microRNA-21 is potentially useful tools as novel noninvasive biomarker for the diagnosis of ovarian carcinoma. Combined microRNA-21 and CA125 is a more accurate predictor of malignancy than either alone.