Molecular evaluation of proliferative-phase endometrium may provide insight about the underlying causes of infertility in women with endometriosis

To determine if endometrial gene expression is different in women with endometriosis-related infertility and fertile women. Prospective study of mid-follicular phase endometrium in 47 subjects in two phases: microarray study of 10 infertile women with endometriosis and five fertile controls, and a quantitative real-time PCR (qRT-PCR) study of 27 infertile women with endometriosis and 15 fertile controls. Gene expression was determined by DNA microarray, and qRT-PCR used for 12 promising genes based on the microarray analysis. Compared to fertile controls, women with stage I-II endometriosis had 23, and women with stage III-IV had 35 genes that were significantly up- or down-regulated by microarray. However, using qRT-PCR, only chemokine ligand (CXCL) 13 was significantly down-regulated and somatostatin was significantly up-regulated with early endometriosis, and only CXCL 14 was significantly down-regulated with advanced endometriosis compared to fertile controls. Our findings indicate that the pattern of gene expression in proliferative-phase endometrium is different when comparing tissue from patients with endometriosis versus fertile controls. Recognition of these endometrial alterations could be helpful to diagnose and stage endometriosis, and may provide insight to explain why conception rates are low in women with endometriosis.