Is endometrial receptivity transcriptomics affected in women with endometriosis? A pilot study

Endometrial receptivity is still questioned today in women with endometriosis. The aim of this study was to assess the endometrial receptivity gene signature in patients with different stages of endometriosis by investigating transcriptomic modifications of their endometrium using the endometrial receptivity array (ERA) test. A prospective, interventional multicentre pilot trial was designed and implemented in two university-affiliated infertility units from Belgium and Spain. Gene expression microarray was used to diagnose the receptivity status by quantifying the expression of 238 specific genes directly related to human endometrial receptivity. Unsupervised hierarchical clustering showed no clustering of samples based on endometriosis stages. Two subgroups of samples clustered together corresponding on the day of the cycle in which the biopsy was taken (day 18 versus days 19-20). None of the 238 genes present in the ERA array were significantly over- or under- expressed in any of different stages of the disease compared with controls. Minimal differences were found when looking at the functional profile, suggesting that the possible effect from a clinical point of view may be meaningless. Endometrial receptivity gene signature during the implantation window does not vary significantly among patients with endometriosis even considering different stages compared with healthy women.