Monocytes/macrophages and natural killer cells characterize the tumor microenvironment of inflammatory breast cancer in Egyptian patients.

Abstract

Abstract Abstract #1054 Background: Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer. IBC incidence appears to be higher in Egypt as compared to USA. Although the role of leukocytes in regulating breast cancer dissemination has been studied extensively, their role in IBC progression is not well understood. Previously, we showed that human monocytes augment the invasiveness and proteolytic activity of IBC cell lines. Aim: To compare the immunophenotype of IBC and non-IBC and to identify IBC tumor-infiltrated immune cell that may be associated with poor prognosis of IBC.
 Methods: We enrolled two groups of patients: IBC (n=13) and non-IBC (n=27) being treated at Ain Shams University hospitals. All patients underwent modified radical mastectomy. IBC patients had 7 or more metastatic axillary lymph nodes whereas non-IBC patients had 3 or less metastatic axillary lymph nodes. During surgery, blood draining from the breast tumor microenvironment, through branches of axillary vein, and peripheral blood was collected. Total mononuclear cells were isolated from collected blood and their phenotype was examined using flow cytometry. Monoclonal antibodies specific for cell surface markers for particular cells types were used: namely T-helper cells (CD3+CD4+), T-cytotoxic cells (CD3+CD4-), natural killer (NK) cells (CD56+) and monocytes/macrophages (CD14+). Results: Within each group we compared the leukocytic composition of blood collected from the tumor drainage to that of peripheral blood in IBC and non-IBC patients. 1) In IBC, we detected a significant increase in the mean percentage of NK cells and monocytes collected from the tumor site, but no significant difference in CD8+ and CD4+ cells. 2) In non-IBC, the percentage of CD4+ T cells collected from the tumor site was significantly higher than from peripheral blood. No significant differences were detected in CD8+, CD56+ and CD14+ cells.
 We compared the leukocyte composition of blood collected from both IBC and non-IBC patients. 1) In peripheral blood of IBC patients, we detected a significant increase in CD4+ T cells, but no significant differences in CD8+, CD56+ and CD14+ cells when compared to non-IBC patients. 2) When we compared the leukocyte content of blood collected from the tumor site in IBC and non-IBC, we found a significant increase in CD56+, and CD14+ cells and a significant decrease in CD4+ T cells in IBC, but no significant difference in CD8+ T cells. Conclusion: Differences in the immunophenotype of IBC versus non-IBC suggests a role for these immune cells in the metastatic dissemination and progression of IBC. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1054.