Nm23 gene product expression in invasive breast cancer--immunohistochemical analysis and clinicopathological correlation.

The nm23 gene/protein is a putative metastatic suppressor identified a decade ago in a melanoma cell line. A number of laboratory, clinical and pathological studies have been carried out to define its real biological and biochemical function as a step in a complex metastatic process. In our study we examined the significance of nm23 expression in 164 breast cancer patients, aged 35 to 74 years, in comparison to other parameters such as age, menopausal status, histological grade, tumor size, lymph node status, and hormone receptor status. Overall survival (OS) and disease-free survival (DFS) were analyzed. The median follow-up was 84 months. Significant changes in OS were found for tumor size, nodal involvement and histological grade but there was no convincing correlation with nm23 expression. When patients were stratified according to nm23 expression, it was shown that overall survival in nm23-positive patients was no longer than that in nm23 negative patients. It was also shown that patients who were lymph node negative and older than 50 years had longer OS than nm23-negative patients. A statistical analysis shows that there is a correlation between axillary node status and nm23 expression (p = 0.018) as well as between patients' ages and nm23 expression (p = 0.043). There was no statistically significant correlation between nm23 expression, lymph node status and their combination on DFS.