EXPRESSION OF NM23 PROTEIN IN PULMONARY ADENOCARCINOMAS - INVERSE CORRELATION 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 prot ein expression in primary tumors was shown to correlate inversely with advancing pathologic stage and the degree of metastasis in regional l ymph nodes (P < 0.05). The staining of tumors without nodal metastasis was more intense than with nodal metastasis (P < 0.02). Nodal metasta sis was seen in 37% (55/147) cases examined. The immunoreactivity to n m23 protein in tumor cells of nodal metastasis was essentially the sam e as in those of primary tumors (P < 0.01). Significant correlation be tween patient prognosis and immunoreactivity for nm23 in primary tumor s (P < 0.05) was demonstrated. But none could be found between immunor eactivity and other parameters such as histologic grading, distant met astasis, tumor size or disease-free survival. Neither was there any si gnificant correlation between pathologic parameters examined and the e xpression of nm23 in any histologic subtype. Multivariate analysis usi ng Cox's proportional hazards regression model with five variables ind icated nm23 and lymph node metastasis to contribute to overall patient survival. Based on risk ratio disadvantageous state/advantageous stat es, the gravity of prognostic factors was assesed for lymph node metas tasis as 9.25, nm23 expression as 2.06, distant metastasis as 1.23, pa thologic stage as 0.78 and tumor size as 0.77. The results suggested t hat in pulmonary adenocarcinoma a reduced expression of nm23 protein w as associated with lymph node metastasis and poor patient survival. (C ) 1997 Elsevier Science Ireland Ltd.