Circulating cell-free DNA concentration in patients with endometriosis: impact of lesions location

Is there an association between the circulating Cf-DNA (CCf-DNA) and the location of the endometriotic lesions ?. This was an retrospective study using serum prospectively collected from non-pregnant patients from the Cochin Hospital who were between 18 and 41 years of age (mean ± sem: 31.5 ± 0.6 years), and who underwent surgery for symptomatic benign gynecological conditions between January 2011 and December 2013. Surgery was performed on 76 patients with signed consent and available preoperative MRIs. After a thorough surgical examination of the abdomino-pelvic cavity, 55 women with histologically proven endometriosis and/or adenomyosis were allocated to the endometriosis group and 52 symptomatic women without evidence of endometriosis with or without adenomyosis to the endometriosis free group. CCf-DNA was extracted from 200 μl of serum and quantified by quantitative PCR using specific primers amplifying ALU115 sequences in both groups and according to surgical endometriosis phenotypes (superficial peritoneal, ovarian and deep pelvic endometriosis). CCf-DNA concentrations were similar in the endometriosis free group with or without adenomyosis. The concentration of CCf-DNA (mean±SEM) was significantly higher in the endometriosis group than in the control group (311±60 vs 144±13 fg/μL, p=0.002). ROC analysis demonstrated a good sensitivity (78.1) and specificity (71.1) (AUC=0.78, p<0.0001). In addition, accordingly to the location of the endometriotic lesions, the CCf-DNA concentrations was significantly increased in the deep pelvic endometriosis (359±110 vs 144±13 fg/μL, p=0.0031) and the superficial peritoneal endometriosis (289±43 vs 144±13 fg/μL, p=0.01) compared with control group, but not in ovarian endometriosis 207±20 vs 144±13 fg/μL, p=0.08). These findings of significantly increased concentrations of CCf-DNA in serum of patients with endometriosis suggests that CCf-DNA might be a potential biomarker for developing non-invasive diagnostic test in endometriosis.