Expression of maspin in endometrioid adenocarcinoma of endometrium

Maspin is a member of the serpin family, whose expression is altered in neoplasia and malignancies of many tissues. Underexpression of maspin has been reported in breast and prostatic cancers, but in some cancers such as ovarian, colorectal and pancreatic carcinoma, it was found to be up-regulated. This study aimed at demonstrating the expression of maspin in human endometrial tissue and searching for any altered expression in endometrioid adenocarcinoma of the endometrium compared to normal endometrium. The expression level of the maspin gene was studied using reverse transcriptase-polymerase chain reaction (RT-PCR) performed on RNA extracted from 34 endometrial cancer samples (including 24 with FIGO stage I disease and 10 with FIGO stage III disease) and 28 normal endometrium in proliferative or secretory phases. Immunohistochemical staining was also performed on 10 cases of endometrial cancer (6 FIGO stage I cases and 4 FIGO stage III cases) as well as 15 normal endometrium. Semi-quantitative RT-PCR revealed that the expression of maspin was significantly up-regulated in both stage I (p<0.01) and stage III (p<0.01) endometrial cancer compared with normal endometrium. However, no significant difference in maspin expression was demonstrated between stage I and stage III endometrial cancer. Immunostaining of all tissue sections revealed an immunopositive signal in the nuclei of the normal or cancerous endometrial glandular cells. In 60% of the cancer cases, cytoplasmic staining was also evident. Our results suggested that there is up-regulated expression of maspin in endometrioid endometrial adenocarcinoma. Cytoplasmic immuno-expression of maspin is common in endometrial cancer. It may play a role in the malignant transformation of human endometrial tissue.