Expression of OLR1 gene on tumor-associated macrophages of head and neck squamous cell carcinoma, and its correlation with clinical outcome.

Head and neck squamous cell carcinoma (HNSCC) is one of the most heavily immune infiltrated human tumors, having distinct immune subtypes associated with different molecular characteristics and clinical outcomes. The tumor microenvironment (TME) of HNSCC which was dominated by tumor-associated macrophages (TAMs) had a relatively inferior prognosis. High levels of oxidized low-density lipoprotein receptor 1 (OLR1) expression are associated with more aggressive and metastatic characteristics in multiple cancers. However, the link between the OLR1 expression and immunosuppression of TME, and the molecular mechanisms which govern intratumoral TAMs behavior are unclear. Here, we performed the transcriptional analysis based on a single-cell RNA-sequencing (scRNA-seq) dataset of HNSCC, and found that the OLR1 expression was specifically enriched on the TAMs. Evaluation of protein expression within histologic sections of primary HNSCC patient samples showed a co-expression pattern of OLR1 and CD68 on macrophages. A total of 498 tumor samples of HNSCC patients from The Cancer Genome Atlas (TCGA) database were also analyzed. Remarkably, OLR1 expression was dramatically higher in HNSCC tissues than that in adjacent normal tissues, and the patients with high levels of OLR1 expression had significantly unfavorable overall survival (Hazard Ratio = 1.724, log-rank P-value = 0.0066) when compared to patients harboring low expression levels of OLR1. In summary, we reported that the specific expression of OLR1 on the TAMs was significantly correlated with poor survival outcomes, revealing that OLR1 could serve as a potential prognosis marker and promising target for immunotherapy in HNSCC.