The Expression Pattern of Endometrial Receptivity Genes is Desynchronized Between Endometrium and Matched Endometriomas.

Research question: Are paired samples of endometrium and ovarian endometriomas synchronous with each other throughout the menstrual cycle? Design: The expression levels of 57 endometrial receptivity-associated genes were determined from matched endometrial and endometrioma samples (n=31) collected from women with endometriosis throughout the menstrual cycle. Results: The expression profile of endometrial receptivity genes divided endometrial samples according to their menstrual cycle phase. Endometrioma samples grouped together irrespective of the menstrual cycle phase and formed a cluster distinct from endometrial samples. Pairwise comparison showed 21, 16, 33 and 23 differentially expressed genes (adjusted P < 0.001-0.05) between the lesions and endometria collected in the proliferative, earlysecretory, mid-secretory and late-secretory menstrual cycle phases, respectively, confirming the distinct expression profiles of endometrium and endometrioma. Conclusions: No menstrual cycle synchronicity was found between matched eutopic and ectopic endometrium, suggesting that the concept of cycling endometrial tissue inside the endometrioma should be revised.