PI3K/AKT pathway is altered in the endometriosis patient's endometrium and presents differences according to severity stage.

Based on the inflammatory nature and hormone-dependency of endometriosis, PI3K/AKT signaling appears to influence its progression. Could the endometriosis stages be linked to differential changes in PI3K/AKT pathway regulation? The objective is to evaluate the expression of PI3K, PTEN, AKT and p-AKT in endometrial human biopsies, according to the presence or absence of the disease, and to assess the underlying differences regarding the endometriosis stages. Biopsy specimens of the ectopic and eutopic endometrium were obtained from twenty women with untreated peritoneal endometriosis as well as endometrium biopsies from nine controls. Our study revealed an increased expression of PI3K in eutopic and ectopic endometrium from patients with endometriosis, and a reduced expression of PTEN and increased levels of AKT phosphorylation, compared to control endometrium. Both eutopic and ectopic endometrium from patients with minimal-mild endometriosis expressed a significant reduced PTEN level compared to the respective endometrium from patients with moderate-severe endometriosis. The ratio p-AKT/total AKT showed higher levels of AKT phosphorylation in endometriotic tissue from patients with minimal-mild endometriosis. This study has firmly confirmed the alteration in PI3K/AKT pathway regulation and demonstrated clear differences between the stages of endometriosis, emphasizing the importance of this pathway in the first stage of the disease.