Objective: To explore the relationships between
S100A7
and the immune characteristics, tumor heterogeneity, and tumor stemness pan-cancer as well as the effect of
S100A7
on chemotherapy sensitivity in breast cancer.
Methods: TCGA-BRCA and TCGA-PANCANCER RNA-seq data and clinical follow-up survival data were collected from the University of California Santa Cruz database. Survival analyses were performed to explore the relationship between
S100A7
expression and pan-cancer prognosis. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, and Gene Set Enrichment Analysis (GSEA) were used to identify the potential pathways related to the differentially expressed genes in breast cancer. Spearman’s and Wilcoxon’s tests were used to investigate the relationships between
S100A7
expression and immune characteristics, methylation, tumor heterogeneity, and tumor stemness. The potential functions of
S100A7
and its influence on chemotherapy sensitivity in breast cancer were elucidated using reverse transcription-quantitative PCR, Cell Counting Kit-8 (CCK-8) assay, Transwell assay, and wound healing assay.
Results:
S100A7
was highly expressed in most types of tumors and was associated with poor prognosis.
S100A7
was closely associated with immunomodulators, immune checkpoint and immune cell infiltration. Further,
S100A7
was related to tumor mutational burden, tumor heterogeneity, methylation and tumor stemness in breast cancer. High
S100A7
expression was associated with the invasiveness, migration, proliferation and chemotherapy resistance of breast cancer cells
in vitro
experiments.
Conclusion: High
S100A7
expression was related with poor prognosis and chemotherapy resistance in breast cancer, making it a potential immune and chemotherapy resistance biomarker.