PAEP and endometriosis: Several markers have been studied for the diagnosis of endometriosis, including cancer antigen (CA)-125 [28,29], CA-72-4 [30], CA 15-3 and CA 19-9 [31], enolase/creatine [32], protein PP14 [33], and TATI [34], but they have been shown to be insufficient to replace surgery and histology due to low sensitivity in the detection of endometriosis [31].