Immunohistochemical analysis of nm23 gene product in human gallbladder carcinomas

The expression of nm23, the product of a candidate suppressor gene for tumour metastasis, was examined immunohistochemically in human gallbladder carcinomas and compared with clinicopathological features. Seventy-eight (72%) of 107 carcinomas expressed nm23 protein regardless of histological type, while non-neoplastic mucosa occasionally showed very weak immunoreactivity to nm23. No obvious correlation was observed between nm23 protein expression and depth of tumour invasion or tumour stage. The expression of nm23 protein was detected in 60% and 74% of the cases with and without lymph node metastasis, respectively, indicating no relationship to metastatic ability. Fifty-eight percent of the cases showed reduction of nm23 immunoreactivity in tumour cells invading the stroma at the border of tumour cell nests compared with cells at the centre of the tumour. Only 7% of the cases showed increased nm23 expression in tumour cells at the border. These results suggest that in gallbladder carcinoma decreased expression of nm23 may not have implications for metastasis but may play a part in local invasion.