The number of lymphoma-associated macrophages in tumor tissue is an independent prognostic factor in patients with follicular lymphoma.

The clinical course of patients with follicular lymphoma is variable from a slowly progressive disease to a progressive disease with a survival time of approximately 1 year. Many prognostic models have been suggested to identify high-risk patients. Recent gene profiling analysis showed that the clinical behavior of follicular lymphoma is determined by the properties of the nonmalignant tumor microenvironment. We investigated the role of lymphoma-associated macrophages (LAMs) in tumor tissue in patients with newly diagnosed follicular lymphoma. The LAM was determined immunohistochemically in lymph node tissue sections by anti-CD68 PG-M1 and analyzed through high-power field (HPF) magnification intrafollicularly (IF) and extrafollicularly. In our study, the patients who had an IF LAM count equal to or more than 10/HPF had significantly shorter overall survival (P=0.018) and 3 years of progression-free survival (P=0.034) compared with patients with <10 LAM/HPF. Multivariate analysis indicated that IF LAM/HPF ≥ 10 and Eastern Cooperative Oncology Group performance status >1 are independent prognostic factors for a poor outcome.