Prognostic value of S1PR1 and Correlations with Immune Infiltrates in Breast and Lung Cancers

Sphingosine-1-phosphate receptor (S1PR1) is involved in vascular development, a key process in tumorigenesis. Our study evaluated its roles in tumor development and prognosis. In particular, S1PR1 expression data were obtained from the TIMER and Oncomine database. We used a bioinformatics approach to evaluate its relationship with prognosis, co-expressed and regulatory genes, correlations with tumor immune cell infiltration and correlations with immune infiltration markers. S1PR1 was significantly lower expression in breast and lung cancer than in corresponding normal tissues. Lower S1PR1 expression was related to poor overall survival and disease-free survival in breast and lung cancer. A functional network analysis suggested that S1PR1 regulates vasculogenesis. In addition, S1PR1 levels were significantly related to infiltrating CD8 + , CD4 + T cells, macrophages, and neutrophils in breast invasive carcinoma; CD8 + T cells, macrophages, neutrophils, and DCs in lung adenocarcinoma; and with B cells, CD8 + , CD4 + T cells, macrophages, neutrophils and DCs in lung squamous cell carcinoma. Furthermore, S1PR1 levels were correlated with multiple immune marker sets in breast and lung cancer. The observed correlations between S1PR1 and both prognosis and immune cell infiltration provide a foundation for further research on its immunomodulatory role in cancer.