Relationship of Nm23 expression to proliferation and prognosis in malignant melanomas of the oral cavity

Twenty-nine cases of oral melanomas were investigated for nm23 and Ki67 antigen expression, as well as for the fraction of tumour cells in S-phase, using immunohistochemical techniques and DNA cytophotometry. Nm23 expression was significantly reduced and Ki67 antigen expression increased in primary tumours with either lymph node or organ metastases in comparison to tumours without metastases. The percentages of Ki67 immunoreactive tumour cells and cells in S-phase correlated positively with each other and negatively with the percentage of nm23-expressing cells. These data argue against a significant growth stimulatory function of the nm23H1 gene product nucleoside diphopshate kinase in the progression of oral melanomas. The functional relevance of nm23 in relation to increased proliferation and metastatic spread is discussed.