Study on relationship between chemokines and immune activation phenotype of breast cancer.

Abstract

e12564 Background: Breast cancer is one of the most common malignant tumors in women. The incidence rate and mortality rate are increasing year by year. Studies have shown that chemokines may act as an important driver in the immune microenvironment of breast cancer. Understanding the potential immunobiological driving effect in breast cancer is important for the early diagnosis of breast cancer, which is helpful to determine the immunotherapy strategy for patients. Methods: Gene expression data of 1050 cases of breast cancer were downloaded from TCGA database. Cluster analysis was applied to investigate the level of immunity of the observations using ssGESA software. The observations were divided into three groups according to their immune score. The expression of CXCL9, CXCL10, CCL4 and CCL5 chemokines were checked for the three groups using PHEATMAP software. The differential expression analysis for the three groups was performed using Edger software. The enrichment analysis was conducted using clusterprofiler software. Results: Cluster analysis showed that the observations could be divided into three subgroups according to their immunity score, and the heatmap proved that expression level of CXCL9, CXCL10, CCL4 and CCL5 chemokines of the subgroup with high immune score were apparently higher than that of the other two subgroups. The differential expression analysis revealed that the expressions of T cell exhaustion genes were markedly different between high-level group and low-level group. A total of 402 differentially expressed genes were identified, among which 380 were up-regulated in high-level group, comparing to low-level group, and 22 were down-regulated in high-level group, comparing to low-level group. Enrichment analysis indicated they were enriched in T cell-related pathway, such as th17, th1, th3 cell differentiation and so on. Conclusions: Our study showed that the expression of four chemokines were obviously different between the groups with high immune score and low immune score. Observations with high expression of four chemokines had more active levels of immune infiltration. Differentially expressed genes were enriched in T cell-related pathway. These four chemokines could be potential biomarkers for breast cancer patients through their unique immune characteristics.