Infiltrating Immune Cells And Tumor Secretion Of Cytokines Expression Differ In Tumor Microenvironment Of Breast Cancer

ObjectiveTumor immune microenvironment plays an important role in the evolution of breast cancer. The tumor infiltration Foxp3+Tregs can be used as independent predictor of poor prognosis in breast cancer (BC). However, how the tumor associated cytokines activating the Foxp3+Tregs infiltration and the differential expression of tumor infiltrating immune cells in different locations are not yet completely understood. The purpose of this study is to joint evaluation of the role of cytokine CCL22and TGF-β1within activation cascade process of Foxp3+Tregs, and to explore the prognostic significance of the two cytokines for BC patients; Comparative analysis differences of infiltrating immune cells between the different pathological types of Basal-like subtype BC.Methods417cases of primary invasive breast cancer tissue with not receive any preoperative anti-tumor therapy were selected and the expressions of Foxp3+Tregs, tumor secretion of CCL22and TGF-β1were assessed by immunohistochemistry for their clinicopathological features, the associations with BC patient survival and molecular subtypes. Meanwhile, we observed the density and distribution of Foxp3+Tregs in BC tissues, and further clarify the association between these cytokines and Foxp3+Tregs in different location in BC tissues.32cases of different pathological types of Basal-like subtype BC were detected by immunohistochemistry for the expression infiltrating immune cells in different locations, including tumor intraepithelial, tumor stroma, and tumor periphery. Further analysis the expression differences of immune cells between two pathological types of Basal-like subtype BC with different prognosis.Results1. The localization and the infiltrating patterns of Foxp3+Tregs vary were observed within the tumor bed and the tumor periphery. 2. Increased infiltration of Foxp3+Tregs within tumor bed was significantly related to the unfavorable prognosis of patients, including high histological grade (P<0.0001), negative ER and PR status (P<0.0001), and HER-2amplification (P=0.001). In addition, intratumoral Treg infiltration was associated with decreased OS and PFS (OS:P=0.013, RFS:P=0.017).3. High expression of tumor secretion of CCL22was found to be associated with the tumor histologic features known to be related with unfavorable prognosis of patients, including high histological grade (P<0.0001), negative ER (P<0.0001), negative PR (P=0.001), and HER-2overexpression (P=0.028), and negatively related to OS and PFS as well(OS:P=0.001, RFS:P=0.002).4. In multivariate analyses, both Foxp3and CCL22were the independent prognostic factors of OS and RFS (P<0.05).5. It was identified that tumor secretion of CCL22was positively correlated with the intratumoral Foxp3+Treg infiltration (P<0.0001), but its association with peritumoral Foxp3+Treg infiltration was not proven to be significant.6. The density of Foxp3+Treg infiltrates within tumor bed significantly increased as the prognosis of the subtypes (luminal A, luminal B, luminal HER-2, HER-2-enriched, and Basal-like subtype) was ranked from well to poor, a similar association was identified at current study between tumor-derived CCL22expression and the molecular subtypes of BC (P<0.0001).7. In contrast, although TGF-β1expression was positively correlated with Foxp3+Tregs infiltrates at both tumor bed and tumor periphery (P=0.029; P=0.048, respectively), its expression was not significantly associated with the molecular subtypes of BC and the prognosis of the patients.8. The localization and the infiltrating density of infiltrating immune cells vary were observed within breast tumor cells and tumor microenvironment of Basal-like subtype BC:high density of GrB+lymphocytes was in tumor intraepithelial and the tumor stroma, T-bet+lymphocytes and CD68+macrophages were in tumor periphery.9. Basal-like subtype BC was divided into two groups according to the different prognostic differences. And found that the density of infiltrate GrB+lymphocytes in tumor intraepithelial, T-bet+lymphocyte in tumor intraepithelial and tumor stroma, and CD68+macrophages in tumor periphery were higher than IDC (P<0.0001; P=0.001, P=0.002; P=0.006; respectively).ConclusionsThe density of intratumoral infiltration of Foxp3+Tregs was an independent factor for poor prognosis of BC patients and correlated with the molecular subtypes of BC. Both CCL22and TGF-β1are candidate chemoattractants for intratumoral Foxp3+Tregs infiltration. Furthermore, CCL22is an independent prognostic predictor of breast cancer patients, and it therefore may have the potential to serve as a target for immunotherapeutic strategy for BC patients. In addition, we have chosen two pathological types of Basal-like subtype BC according to the different prognostic differences, the MC group and IDC group. Comparative analysis of their density and distribution of infiltrating immune cells, confirming the GrB+lymphocytes, T-bet+lymphocytes, and CD68+macrophages are significant differences in two groups, which may be th e real reason for their different prognosis. It may be provide a potential immune target for Basal-like BC patients whom were not suit for endocrine and HER-2targeted therapy.