Evaluation of PTEN and Ki67 Expression in Typical and Atypical Endometriosis and Endometriosis Associated Ovarian Cancer

Abstract

Background: Several studies reported that endometriosis is associated with an increased risk of ovarian cancer. Atypical endometriosis is common in patients with endometriosis-associated ovarian, which might be considered as a precancerous lesion. Objectives: This study aimed to assess ki67 and PTEN expression in endometriosis associated ovarian cancer (EAOC), atypical endometriosis, and typical endometriosis. Methods: In this study, all H & E slides of 260 ovarian endometriosis cases were reviewed. And 25 cases were diagnosed with atypical endometriosis. Forty-one typical endometrioses and 24 ovarian cancers with endometriosis were included. We assessed PTEN and Ki67 immunoexpression in epithelial and stromal cells. Results: The prevalence of atypical endometriosis was about 9%. PTEN loss was found in 12 (out of 24 or 50%) of EAOC, 2 (out of 25; 8%) of atypical endometriosis, and none of the typical endometriosis. In all 12 PTEN loss cases, the PTEN loss pattern in endometriosis adjacent to ovarian cancer was similar to that of ovarian cancer. A total of 7.3% of typical endometriosis and 8% atypical endometriosis and 33.3% of EAOC had Ki67 staining in more than 50% of the epithelial component. Both typical and atypical endometriosis showed similar PTEN loss and Ki 67 staining (in more than 50% of the epithelial component) (P value > 0.05), and both of them were different from EAOC (P value < 0.05). Conclusions: The PTEN loss pattern in endometriosis adjacent to ovarian cancer was similar to that of ovarian cancer. The result indicated that PTEN loss could be an early event in the tumor development pathway from endometriosis to ovarian cancer.

Histologic Subtypes in Endometriosis-Associated Ovarian Cancer and Ovarian Cancer Arising in Endometriosis: A Systematic Review and Meta-Analysis

“…We also selected 12 studies in which ovarian cancer was defined as “arising in” endometriosis (Sampson and Scott’s criteria) (SF4). Three studies described ovarian cancer cases as “associated with” endometriosis, but since the authors defined cases as meeting Sampson and Scott’s criteria, we included them as OCAE [ 33 – 35 ]. Three studies also included cases of extra-ovarian cancer [ 12 , 13 , 36 ].…”

“…The genes involved in endometriosis and epithelial ovarian cancer have been shown to play a role in the pathogenesis of malignant transformation [ 43 ]. PTEN loss may be an early event in cancer development from endometriosis [ 35 ], as well as genetic mutations affecting ARID1A and PIK3CA seem to play a role [ 3 ]. Although mutation or loss of function of the p53 tumour suppressor gene is rare in endometriosis, it may play an important role in malignant transformation and is the most common and important genetic event in the development of ovarian cancer.…”

At what age endometriosis-associated ovarian cancer is diagnosed? The implications for women in the reproductive age

“…Eighteen studies assessed all cases of EAOC combined ( 21 – 23 , 25 , 29 , 32 , 34 – 39 , 41 – 43 , 46 – 48 ), six evaluated only patients with clear-cell ovarian cancer associated with endometriosis ( 24 , 28 , 33 , 40 , 44 , 45 ), and one study endometrioid ovarian cancer associated with endometriosis ( 27 ). In addition, six eligible studies were performed in countries with a higher prevalence of EAOC, in Japan, Thailand, and Taiwan ( 22 , 24 , 38 , 39 , 42 , 43 ).…”