High expression of tumor-infiltrating macrophages correlates with poor prognosis in patients with diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is characterized by its clinical and biological heterogeneity. Although the International Prognostic Index (IPI) provides a clinical model for risk stratification of patients with DLBCL, notable variability in outcome is still observed within the same IPI category. Tumor-infiltrating macrophages (also called Tumor-associated macrophages) are the major component in the microenvironment of DLBCL. Their correlation with the prognosis of DLBCL remains controversial. Using a CD68 antibody in immunohistochemical analysis, we studied the expression of CD68 in 112 Chinese patients with DLBCL, with 65 patients (58%) categorized as low CD68 expression and 47 patients (42%) as high CD68 expression. The complete response (CR) rate of patients with low CD68 expression was higher than that with high CD68 expression (66.1% vs. 51.6%), but there was no statistical significance (P = 0.060). The median survival time of patients with low CD68 expression was not achieved and that of high expression was 41 months (P = 0.029). The results suggest that higher expression of CD68 tended to yield poor treatment outcome of DLBCL.