Coexpression of survivin and PCNA in pituitary tumors and normal pituitary.

ABSTRACT

OBJECTIVES: The survivin is the protein involved in regulation of basic and cycle-specific functions of cells both in normal and cancer tissue. Recent studies present survivin as a factor having the leading role in the regulation of apoptosis and mitosis as well as a target of anticancer therapy. The employing of survivin in this therapy is based on its high expression level in most human cancers, as well as its association with the disease's progression. The aim of our study was to evaluate the expression and localization of survivin's gene product on the protein level in different types of pituitary tumors and normal pituitary. The coexpression of survivin and proliferating cell nuclear antigen - PCNA in pituitary was also examined. DESIGN AND METHODS: The study was conducted on the postoperative pituitary tumors tissue taken during standard neurosurgical removal of tumor from 43 patients. The group of patients consists of 23 women and 20 men, aged from 27 to 71 years. As a control of the study three normal pituitary tissues obtained at the autopsy were used. Evaluation of survivin and PCNA expression was performed using immunohistochemical staining. RESULTS: The study demonstrated the presence of survivin in all analyzed by us pituitary tumors. Survivin was present also in normal pituitary tissue. The protein was localized mainly in cell's nuclei, however the less intense immunostaining was observed also in the cytoplasm of pituitary tumors cells. Furthermore survivin was found in normal pituitary, but the positive immunostaining was limited to a single cells. The analysis of pituitary tumor cells proliferation index based on PCNA reactivity showed that survivin is coexpressed with PCNA, especially in invasive tumors. CONCLUSIONS: The study documented the presence of survivin in different types of pituitary tumors as well as in normal pituitary. Additionally the coexpression of survivin and PCNA in tumor cells was shown. The expression of survivin in both normal and cancer pituitary cells suggests that it may play an important role in regulation of the gland's proliferation.