A comprehensively prognostic and immunological analysis of chloride intracellular channel protein 5 (CLIC5) in pan-cancer and identification in ovarian cancer.

CLIC5 encoded protein associates with actin-based cytoskeletal and is increasingly thought to play significant roles in human cancers. We use TCGA and GEO to explore CLIC5 expression differences, mutation and DNA methylation, TMB, MSI, and immune cell infiltration. We verified the mRNA expression of CLIC5 in human ovarian cancer cells by real-time PCR and detected the expression of CLIC5 as well as immune marker genes in ovarian cancer by immunohistochemistry. The pan-cancer analysis showed that CLIC5 is highly expressed in several malignant tumors. In some cancers, CLIC5 expression in tumor samples is associated with poorer overall survival. For example, patients with ovarian cancer with high expression of CLIC5 have a poor prognosis. CLIC5 mutation frequency increased in all tumor types. The CLIC5 promoter is hypomethylated in most tumors. CLIC5 was associated with tumor immunity and different immune cells of different tumor types, such as CD8 T cells, tumor-associated fibroblasts, macrophages, etc. CLIC5 was positively correlated with various immune checkpoints, and TMB and MSI were correlated with dysregulation of CLIC5 in tumors. The expression of CLIC5 in ovarian cancer was detected by qPCR and IHC, and the results were consistent with the bioinformatics results. There were a strong positive correlation between CLIC5 expression and M2 macrophage (CD163) infiltration and a negative correlation with CD8 T-cell infiltration. In conclusions, our first pan-cancer analysis offered a detailed grasp of the cancerogenic functions of CLIC5 in a variety of malignancies. CLIC5 participated in immunomodulation and performed a crucial function in the tumor microenvironment.