Serum galectin-9 as a noninvasive biomarker for the detection of endometriosis and pelvic pain or infertility-related gynecologic disorders.

OBJECTIVE: To investigate the usefulness of soluble galectin-9 (Gal-9) in the noninvasive laboratory diagnosis of endometriosis and various gynecologic disorders.

DESIGN: Prospective case-control study.

SETTING: University medical centers.

PATIENT(S): A total of 135 women of reproductive age were involved in the study, 77 endometriosis patients, 28 gynecologic controls, and 30 healthy women.

INTERVENTION(S): Diagnostic laparoscopy and collection of tissue biopsies, peritoneal cells, and native peripheral blood from different case groups of gynecology patients and healthy women.

MAIN OUTCOME MEASURE(S): The expression of mRNA and serum concentration of Gal-9.

RESULT(S): Semiquantitative reverse transcription-polymerase chain reaction analysis and serum soluble Gal-9 ELISA were performed on three different cohorts of patients: those with endometriosis, those with benign gynecologic disorders, and healthy controls. Differences in the Gal-9 concentrations between the investigated groups and the stability of Gal-9 in the serum and diagnostic characteristics of Gal-9 ELISA were determined by statistical evaluation and receiver operating characteristic (ROC) curve analysis. Significantly elevated Gal-9 levels were found in both minimal-mild (I-II) and moderate-severe (III-IV) stages of endometriosis in comparison with healthy controls. At a cutoff of 132 pg/mL, ROC analysis revealed an excellent diagnostic value of Gal-9 ELISA in endometriosis (area under the curve = 0.973) with a sensitivity of 94% and specificity of 93.75%, indicating better diagnostic potential than that of other endometriosis biomarkers. Furthermore, various pelvic pain or infertility-associated benign gynecologic conditions were also associated with increased serum Gal-9 levels.

CONCLUSION(S): Our results suggest that Gal-9 could be a promising noninvasive biomarker of endometriosis and a predictor of various infertility or pelvic pain-related gynecologic disorders.