Expression of nm23 antimetastatic gene product in parathyroid hyperplasia, adenoma and carcinoma. An immunohistological assessment

OBJECTIVE: The nm23 gene was initially cloned as a metastasis suppressor gene, but the clinical relevance of nm23 as a metastasis suppressor or prognostic indicator for human cancers remain controversial. To evaluate the role of nm23 protein as a prognostic factor and its role in parathyroid neoplasia, we studied nm23 protein expression by immunohistochemical staining in parathyroid lesions.

METHODS: Immunohistochemistry using the avidin-biotin peroxidase complex technique with a polyclonal antibody against the nm23 protein was applied to formalin-fixed, paraffin-embedded tissue specimens obtained from 48 patients. The specimens were collected from 38 patients at the University Health Network, Toronto, Canada and from 10 Saudi patients at the King Abdul-Aziz University Hospital, Jeddah, Kingdom of Saudi Arabia. They included parathyroid carcinomas (5 cases), adenomas (22 cases), hyperplasia (21 cases), and normal parathyroid tissue (10 cases). The immunohistochemistry was completed in 2003 at King Abdul-Aziz University Hospital, Jeddah, KSA and University Health Network, Toronto, Canada.

RESULTS: Expression of nm23 protein was noted in adenomas and carcinomas as well as in hyperplastic parathyroid glands and there was no significant statistical difference between these groups. Normal parathyroid glands did not show any intense immunoreactivity.

CONCLUSION: The results suggest that expression of nm23 in parathyroid lesions is correlated with tumor proliferation rather than suppression of invasion and metastasis. While our data suggest that nm23 may help in the distinction of normal from proliferative parathyroids, these results do not point to nm23 as a reliable prognostic marker in parathyroid lesions.