Bioinformatics and immunohistochemistry analyses of expression levels and clinical significance of CXCL2 and TANs in an oral squamous cell carcinoma tumor microenvironment of <i>Prophyromonas gingivalis</i> infection
Zhichen Guo, Sakendeke Jumatai, Si-li Jing, Lulu Hu, Xinyu Jia, Zhongcheng Gong
Abstract
The present study aimed to detect the immunoexpression and clinical significance of <em>Porphyromonas gingivalis</em> (<em>P. gingivalis</em>) in the tumor microenvironment (TME) of oral squamous cell carcinoma (OSCC). The immunoexpression of <em>P. gingivalis</em> in OSCC tissues was detected via immunohistochemistry (IHC) after <em>P. gingivalis</em> was infected into the TME of OSCC. To identify the differentially expressed genes in the carcinogenesis and progression of OSCC with <em>P. gingivalis</em> infection, microarray datasets (GSE87539 and GSE138206) were downloaded from the Gene Expression Omnibus database. The immunoexpression levels of C‑X‑C motif chemokine ligand 2 (CXCL2) and tumor‑associated neutrophils (TANs) were also evaluated via IHC, and the immunoexpression levels of all three clinical variables were analyzed using χ<sup>2</sup> or Fisher's exact tests. The survival rates were calculated using the Kaplan‑Meier method and the survival curves were compared using log‑rank tests. Predominantly strong immunoexpression of <em>P. gingivalis</em> was identified in OSCC samples. CXCL2 was considered to be a differential gene in the two datasets. Immunoexpression of <em>P. gingivalis</em> was positively associated with CXCL2 and TANs expression. Furthermore, <em>P. gingivalis</em> was associated with survival status (P<0.001) and differentiation (P<0.001). CXCL2 was associated with age (P=0.038) and survival status (P=0.003), while TANs were associated with T stage (P=0.015) and clinical stage (P=0.002). These clinical variables were considered to be independent risk factors for the poor prognosis of patients with OSCC. Collectively, the results suggested that the immunoexpression of <em>P. gingivalis</em> may be positively associated with CXCL2 and TANs. In addition, the strong immunoexpression levels of <em>P. gingivalis</em>, CXCL2 and TANs may be associated with a poor prognosis in patients with OSCC.