Growth Arrest-Specific Protein 6 Is Elevated in Endometriosis but Shows Poor Diagnostic Performance

Growth arrest-specific protein 6 (GAS6) has an important role in regulating the immune system. Recent studies have revealed its association with the pathophysiology of endometriosis and identified GAS6 as one of the hub genes and a biomarker candidate. Endometriosis is a common chronic inflammatory gynaecological disease of women of childbearing age. Due to surgical diagnosis, non-invasive biomarkers are urgently needed. We investigated GAS6 as a candidate biomarker for the diagnosis of endometriosis. Our case–control study included 284 patients and showed that plasma levels of GAS6 are significantly higher in patients with endometriosis compared to control patients. We calculated logistic regression models using GAS6, CA-125, and GAS6 together with CA-125, and added a series of clinical and lifestyle data collected before surgical diagnosis. A CA-125 model and a model including GAS6 and CA-125 showed the highest AUC values of 0.745 ± 0.04, while the model including CA-125, data on sport/recreation before surgery, and dysmenorrhea score reached an AUC of 0.767 ± 0.04. Our results indicate that GAS6 is increased in patients with endometriosis, but it cannot serve as a biomarker candidate.