The gene expression profile of cumulus cells reveals altered pathways in patients with endometriosis.

PURPOSE: The objective of this experimental study was to compare the global gene expression profile of CC of mature oocytes in 18 patients with severe endometriosis and CC in 18 control patients affected by a severe male factor. METHODS: For each group, the CC were pooled, RNA was extracted and a microarray performed. For validating the microarray, a quantitative real-time PCR was performed in the CC of an independent set of patients with endometriosis (n = 5) and controls (n = 7). RESULTS: 595 differentially expressed genes (320 down-regulated, 275 up-regulated, p < 0.05, fold change ≥1.5) were identified. The most significant changes were observed in genes involved in the chemokine signaling and cell-cell or cell-extracellular matrix adhesion pathways. Several genes of these pathways were down-regulated in endometriosis. Individual RT-PCR assays confirmed the microarray for ten genes. CONCLUSIONS: Several genes involved in the chemokine mediated-signaling pathway and in the functional cross-talk between CC and the oocyte are down-regulated in endometriosis CC. The impairment of these processes could explain the reduction of oocyte competence in endometriosis. This preliminary knowledge could be the starting point for a more detailed elucidation of the relationship between endometriosis and oocyte competence.