Nm23 gene expression and its correlation with lymph node metastasis in human lung cancer

Using labelled streptavidin-biotin (LSAB) method, we examined the expression of nucleoside diphosphate kinase(NDPK), the product of metastasis suppressor gene nm23, in human lung cancer. Of 88 patients tested, 48 (54.5%) showed positive staining. The positive staining rate was higher in adenocarcinoma (28/42, 66.7%) than in squamous cell carcinoma (20/46, 43.5%; P < 0.05). Higher incidence of positive staining was also found in squamous cell carcinoma without hilar or mediastinal lymph node metastasis (16/27, 59.3%) than in that with hilar or mediastinal lymph node involvement (4/19, 21.1%; P < 0.05). NDPK/nm23 was equally expressed in adenocarcinoma irrespective of lymph node status. In both cell types of carcinoma, expression of NDPK/nm23 was not correlated with tumor cell differentiation, nor was it correlated with the P-TNM staging. Our results suggest that NDPK/nm23 may play different roles in the pathogenesis and metastasis of human pulmonary squamous cell carcinoma and adenocarcinoma. Its expression levels are inversely correlated with lymph node metastasis in squamous cell carcinoma.