Clinical significance of intracytoplasmic nm23-H1 expression in diffuse large B-cell lymphoma

Purpose: Recently, we established an ELISA technique for measuring nm23-H1 protein in serum and found that the serum nm23-H1 level is a potential prognostic factor for patients with non-Hodgkin's lymphoma. Experimental Design: We used immunohistochemistry to examine the expression of nm23-H1 by the lymphoma cells in patients with diffuse large B-cell lymphoma (DLBCL). Results: By analyzing a consecutive series of 172 untreated DLBCL patients, we found that 100 (58.1%) were strongly positive. The cytoplasmic nm23 expression in lymphoma cells correlated significantly with the serum nm23-H1 level. There was a significant correlation between patients with cytoplasmic nm23-positive lymphoma and those with performance status 2-4, stage III/IV, bulky mass, B symptoms, elevated serum level of soluble interleukin 2 receptor, and elevated serum level of C-reactive protein. Overall and progression-free survival rates were significantly lower in patients with nm23-H1-positive lymphomas than in those with nm23-H1-negative lymphomas. Similar difference was seen between patients with high and low serum levels of nm23-H1. Thus, the correlation between presence or absence of cytoplasmic nm23-H1 expression and serum nm23-H1 levels suggests that serum nm23-H1 is produced directly by lymphoma cells. Conclusion: We suggest that nm23-H1 expression is a prognostic factor for DLBCL, and that it is as important as serum nm23-H1, both of which are useful for planning a treatment strategy.