Clusterin is a biomarker of breast cancer prognosis and correlated with immune microenvironment

It has been established that clusterin is involved in the invasion of immune cells in the tumor microenvironment, but it remains unknown how it promotes immune invasion in breast cancer. We used Tumor Immune Estimation Resource (TIMER) and Gene Expression Profiling Interactive Analysis (GEPIA) databases to assess the relation between expression of clusterin and immunoinfiltration-related marker genes. TIMER database was used to evaluate the expression of clusterin, and its relation to tumor immune invasion was examined. Based on Kaplan-Meier plotter database, we investigated the association between clusterin expression and prognosis in patients with cancer, and the impact of clinicopathological factors and cancer-related outcomes. Clusterin expression was markedly associated with prognosis of a variety of tumors, specifically breast cancer. Enhanced clusterin expression was markedly associated with molecular typing of breast cancer and expression of multiple markers related to specific immune cell subsets. These results indicate that clusterin is connected to prognosis of breast cancer patients and tumor immune cell infiltration. This demonstrates that clusterin may be a biomarker of immune cell recruitment into breast tumors and an important biomarker for immune cell infiltration; consequently being a valuable prognostic factor in breast cancer patients.