Abstract
BACKGROUND: This study aimed to screen and identify potential immune biomarker to predict the prognosis of oral squamous cell carcinoma (OSCC). METHODS: Data of OSCC patient from The Cancer Genome Atlas (TCGA) database were downloaded, and the ESTIMATE algorithm was used to calculate stromal and immune scores. Differentially expressed genes (DEGs) between the high and low immune score groups were screened, and Kaplan-Meier survival analysis was performed to identify the DEGs linked to the overall survival (OS) time of OSCC patients. Then, those DEGs were validated in anther cohort. A correlation analysis was used to further screen the prognostic genes which were tightly linked to the expression of programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1). The expression profiles of the candidate genes interleukin 12 receptor subunit beta 1 (IL-12RB1), cytotoxic T-lymphocyte associated protein 4 (CTLA4), and G protein-coupled receptor 25 (GPR25) were identified in the single-cell RNA sequence OSCC dataset from GSE103322. Finally, immunohistochemistry (IHC) and immunofluorescence (IF) were applied to confirm the expression pattern of IL-12RB1 in OSCC tissue microarray. Kaplan-Meier analysis was used to assess the prognostic significance of IL-12RB1 staining score in the malignant and non-malignant cells among the patients. RESULTS: The high immune score group showed better OS compared with that of the low immune scores group. Among 339 DEGs, 90 were identified as being tightly linked to OS time. In the validation set, 23 genes were confirmed to be closely associated with survival prognosis, and the expression levels of IL-12RB1, CTLA4, and GPR25 were commonly associated with the expression of PD-1/PD-L1. The RNA-sequencing showed that IL-12RB1 was expressed in epithelial and immune cells, whereas CTLA4 and GPR25 were relatively poorly expressed in the OSCC tissue. IHC showed that IL-12RB1 was positively expressed in both malignant and non-malignant cells. IF showed that IL-12RB1 was co-expressed with CD3, CD68, PD-1, and PD-L1 on the cytomembrane. Additionally, high score of IL-12RB1 expression in the non-malignant cells was a prognostic risk factor for OS of OSCC. CONCLUSIONS: IL-12RB1 was tightly associated with survival of OSCC and with the expression levels of PD-1/PD-L1 in the tumor immune microenvironment.