Biomarkers for Endometriosis in Saliva, Urine, and Peritoneal Fluid

Endometriosis is a pain syndrome which affects 35–50% of women with chronic pelvic pain and/or infertility. It is frequently misdiagnosed leading to delays in patients obtaining appropriate treatments. The most accurate currently available mode of diagnosis is through laparoscopy with histological confirmation. In this chapter we describe noninvasive and semi-invasive modalities to obtain biologic biomarkers which may be an adequate screening tool for patients with endometriosis who are symptomatic with normal transvaginal ultrasounds, whom are at highest risk for diagnosis delay. In this chapter we will review noninvasive (urinary, salivary) and semi-invasive biomarkers (peritoneal), as screening and diagnostic methodologies for women symptomatic endometriosis and normal ultrasound findings. Few genetic markers have been identified through DNA amplification of buccal swabs as well as hormonal markers, and this is an area with lots of potential. Various urinary peptides and proteins are discussed, some with more potential than others, which require studies with larger sample sizes, and need to be studied in more diverse populations. We also review the extensively studied peritoneal biomarkers which include cytokines, immune modulators, and growth factors. Though many of the biomarkers described have a lot of potential, there is not one that stands above the rest. Validation of these studies in larger sample sizes including various study populations is required prior to their applicability into the clinical setting. It is most probable that the answer lies in the study of combination of biomarkers and the identification of ideal panel that can predict the diagnosis and the severity of endometriosis.