Prognostic value of tumor-associated macrophage count in human bladder cancer

Background: We determined the tumor-associated macrophage (TAM) count to in vestigate its importance in predicting clinical outcome or prognosis in pat ients with bladder cancer. Methods: The TAM count and microvessel count (MVC) were determined immunohi stochemically in 63 patients with bladder cancer, including 40 superficial bladder cancers and 23 invasive bladder cancers. To examine the relationshi p between TAM count and clinical outcome or prognosis in bladder cancer, cy stectomy rates, distant metastasis rates, vascular invasion rates and 5 yea r survival rates were compared between patients with low (< 67) and high (g reater than or equal to 67) TAM counts. Results: The TAM count in invasive bladder cancers (154.22 +/- 11.98) was s ignificantly higher than in superficial bladder cancers (49.05 +/- 7.76; P < 0.0001). The MVC in invasive bladder cancers (71.55 +/- 10.44) was also s ignificantly higher than in superficial bladder cancers (47.02 +/- 5.57; P < 0.05). There was a positive correlation between TAM count and MVC (r = 0. 30; P = 0.02). Immunohistochemical staining using CD68/horseradish peroxida se monoclonal antibody showed more infiltrating cells in invasive than supe rficial bladder cancers. Patients with a high TAM count (greater than or eq ual to 67) showed significantly higher rates of cystectomy, distant metasta sis and vascular invasion than those with a lower TAM count (< 67). The 5 y ear survival rate estimated using the Kaplan- Meier method was significantl y lower in patients with a high TAM count than in those with a low TAM coun t (P < 0.0001). Conclusions: Our results suggest that determination of TAM count in bladder cancer tissues is of value to predict the clinical outcome or prognosis an d to select appropriate treatment strategies in patients with bladder cance r.