A comprehensive investigation regarding the clinical significance of ITGB4 in oral squamous cell carcinoma combining immunohistochemistry, RNA-seq, and microarray data.

Objective: Integrin subunit beta 4 (ITGB4), a receptor for laminins, was an oncoprotein in several malignancies. However, its clinical role in oral squamous cell carcinoma (OSCC) remains unclear.

Materials And Methods: Firstly, 99 OSCC and 13 normal oral epithelium samples were employed for immunohistochemistry (IHC) for detecting the expression level of ITGB4 protein in OSCC. Subsequently, 971 OSCC and 281 non-cancerous specimens from RNA-seq and 18 microarrays were applied for investigating the expression of ITGB4 mRNA. Furthermore, to explore the potential mechanism of ITGB4 in OSCC, the co-expressed genes of ITGB4 were initially screened using all available datasets, and were further utilized for the gene enrichment analysis.

Results: First, IHC showed a distinctively higher expression level of the ITGB4 protein in the OSCC group than that in the normal controls. Second, expression profile from RNA-seq and microarrays reflected that ITGB4 mRNA was dramatically overexpressed in OSCC tissues compared with non-tumor tissues. Third, standardized mean difference (SMD) with the area under the summary receiver operating characteristic (sROC) curve combining all incorporated data revealed that ITGB4 was consistently significantly upregulated in OSCC tissues, with the SMD value being 1.31 and the area under the sROC curve being 0.82. Lastly, 184 upregulated and 179 downregulated co-expressed genes of ITGB4 were utilized for enrichment analysis, which demonstrated that ITGB4 might influence the pathogenesis of OSCC through cell cycle, ECM-receptor interaction and focal adhesion pathways.

Conclusions: ITGB4 might play a pivotal role in the tumorigenesis and progression of OSCC, making it a promising biomarker of OSCC.