High numbers of CD68+ tumor-associated macrophages correlate with poor prognosis in extranodal NK/T-cell lymphoma, nasal type.

Many studies have demonstrated that tumor-associated macrophages (TAMs) were a prognostic indicator in patients with B cell lymphoma. But, we know little about the clinical significance of TAMs in extranodal natural killer/T cell lymphoma(ENKTL), nasal type. CD68 expression was detected using immunohistochemistry to determine the numbers of TAMs in 70 ENKTL patients, and the data were used to evaluate its relationship with clinicopathological features, treatment response, and prognosis. Patients with high number of infiltrated CD68+ TAMs (>60/hpf) at diagnosis tended to have more adverse clinical characteristics. Patients with low CD68+ TAM content (<60/hpf) at diagnosis had better overall survival (P = 0.003) and progression-free survival (P = 0.002) and achieved higher complete remission rates (P = 0.008). Multivariate analysis revealed that CD68 + TAM content, Ki-67 index, and stage III and IV were independent prognostic factors for both OS and PFS. Using the International Prognostic Index or Korean Prognostic Index for extranodal NK/T cell lymphoma, nasal type, the majority of patients were in the low-risk category. CD68 + TAM content was helpful to differentiate the low-risk patients with different survival outcomes. Our data suggest that CD68+ TAM content at diagnosis is a powerful predictor of prognosis for ENKTL, which suggests a role for TAMs in the pathogenesis of this disease and offers new insight into potential therapeutic strategies.