Correlation between nm23-H1 overexpression and clinicopathological variables in human anal canal carcinoma

To improve life expectancy prognostic factors other than TNM have been investigated. It is thought that nm23 protein may play a specific biological role in suppressing tumor metastasis. The purpose of this study was to elucidate the clinical significance of nm23 expression in human anal canal carcinoma. Immunostaining using anti-nm23 monoclonal antibody was performed in 22 anal canal tumors. The results were correlated with clinicopathological variables. Six cases out of 22 (27.3%) were nm23-positive. Significant association was found between nm23-H1 expression and depth of invasion, lymph node involvement and prognosis (p<0.05). There was no significant association between nm23-H1 expression, histologic type and age of the patients. nm23-H1 expression was not seen in our cases with metastasis and this may be related to nm23 gene alterations not being detectable by the monoclonal antibody used or to the presence of a subset of tumors in which nm23 gene abnormalities had not yet occurred at the time of tumor excision or biopsy. Overexpression of nm23-H1 protein in anal canal carcinoma may have implications for its metastatic potential. nm23-H1 expression would provide a more accurate evaluation of outcome for individual patients and thus improve treatment planning.