Expression of nm23 protein in pulmonary adenocarcinomas: inverse 1orrelation to tumor progression

Immunohistochemical assessment was made of nm23 protein expression in pulmonary adenocarcinoma. Of the 147 adenocarcinomas 67% (99/147) were weakly and 33% (48/147) strongly positive for nm23 protein. nm23 protein expression in primary tumors was shown to correlate inversely with advancing pathologic stage and the degree of metastasis in regional lymph nodes (P < 0.05). The staining of tumors without nodal metastasis was more intense than with nodal metastasis (P < 0.02). Nodal metastasis was seen in 37% (55/147) cases examined. The immunoreactivity to nm23 protein in tumor cells of nodal metastasis was essentially the same as in those of primary tumors (P < 0.01). Significant correlation between patient prognosis and immunoreactivity for nm23 in primary tumors (P < 0.05) was demonstrated. But none could be found between immunoreactivity and other parameters such as histologic grading, distant metastasis, tumor size or disease-free survival. Neither was there any significant correlation between pathologic parameters examined and the expression of nm23 in any histologic subtype. Multivariate analysis using Cox's proportional hazards regression model with five variables indicated nm23 and lymph node metastasis to contribute to overall patient survival. Based on risk ratio disadvantageous state/advantageous states, the gravity of prognostic factors was assessed for lymph node metastasis as 9.25, nm23 expression as 2.06, distant metastasis as 1.23, pathologic stage as 0.78 and tumor size as 0.77. The results suggested that in pulmonary adenocarcinoma a reduced expression of nm23 protein was associated with lymph node metastasis and poor patient survival.