CCRL2 and polycystic ovary syndrome: In the PCOS training dataset, the AUCs of ACSL5, NLRP12, CCRL2, and CEACAM3 were 0.828, 0.820, 0.719 and 0.867, respectively (Additional file 3: Fig. S3), indicating their performances in distinguishing PCOS from control samples were great.