Circulating cell-free endometrial DNA level is unaltered during menstruation and in endometriosis

• Published in: Human reproduction (Oxford) 2022-10, Vol.37 (11), p.2560-2569
• Main Authors: Yuwono, N L, Alonso, A, Abbott, J, Houshdaran, S, Henry, C E, Rodgers, R, Ford, C E, Warton, K
• Format: Article
• Language: English
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/humrep/deac198

STUDY QUESTIONIs circulating cell-free DNA (cirDNA) from the endometrium elevated during menstruation and in endometriosis? SUMMARY ANSWEREndometrial cirDNA does not increase during menstruation and is not elevated in endometriosis. WHAT IS KNOWN ALREADYChanges in cirDNA associated with common benign conditions are a potential source of false positives in cancer diagnostic applications, but also present an opportunity for biomarker development for diseases such as endometriosis. Elevated cirDNA has been reported in endometriosis patients compared to healthy community controls, but no difference in total or endometrial cirDNA has been found between patients with endometriosis and patients with other gynaecological conditions. Likewise, menstruation is a potential driver of changes in cirDNA levels and tissue profile, but total and endothelial cirDNA do not increase during menstruation. STUDY DESIGN, SIZE, DURATIONFor endometriosis comparisons, 59 participants with surgically confirmed endometriosis and 27 laparoscopic patients without endometriosis (hospital controls) were prospectively recruited, while 25 healthy community participants (healthy controls) were recruited in a university setting. Total and endometrial cirDNA and cirDNA fragmentation were measured across the three groups. For menstrual comparisons, 36 matched non-menstruating and menstruating samples were collected from healthy women recruited within a university setting, and the endometrial cirDNA was compared between the two groups. PARTICIPANTS/MATERIALS, SETTING, METHODScirDNA was extracted from venous blood plasma then quantitated by quantitative PCR of ALU repetitive element (115 bp) and TP53 gene sequence (105 bp) for total concentration. cirDNA derived from the endometrium was quantitated by methylation-specific droplet digital PCR of a FAM101A region (69 bp) after bisulfite conversion of the DNA. A cirDNA size fragmentation ratio was obtained by quantifying a long segment of ALU repetitive element (247 bp) and expressing the amount relative to the 115 bp ALU target. MAIN RESULTS AND THE ROLE OF CHANCENo differences in cirDNA level were found in any comparison populations in this study. Mean total cirDNA was unchanged between healthy controls (ALU-115-3.31 ng/ml; TP53-2.73 ng/ml), hospital controls (ALU-115-3.47 ng/ml; TP53-2.83 ng/ml) and endometriosis patients (ALU-115-3.35 ng/ml; TP53-2.66 ng/ml). Likewise, endometrial cirDNA was unchanged between healthy controls (18.3 copies/ml),