Akira Iwase

Purpose This study aimed to investigate whether serum leucine‐rich α2‐glycoprotein (LRG) is a useful diagnostic biomarker for endometriosis, including the evaluation of treatment efficacy and exploration of LRG production in endometriotic lesions. Methods Forty‐three women with endometriomas were compared to 22 women with benign ovarian cysts and 30 women who underwent assisted reproduction as controls. Changes in serum LRG levels were assessed before and after surgery, and during dienogest treatment. LRG expression in endometriotic tissue samples was evaluated using immunoblotting. Results Serum LRG levels in the endometrioma group (80.0 ± 36.3 μg/mL) were significantly higher than those in the benign ovarian cyst (65.1 ± 27.0 μg/mL, p = 0.0265) and control (57.8 ± 22.3 μg/mL, p = 0.0028) groups. Serum LRG levels after endometrioma surgery were significantly lower than preoperative levels ( p = 0.0484). Serum LRG levels consistently decreased during dienogest treatment. LRG expression levels were significantly higher in endometriotic tissues than in the normal endometrium. Conclusion Serum LRG, possibly derived from local and systemic origins, could be used as a potential biomarker for the diagnosis and treatment of endometriosis.