Abstract: Objective  To screen the cross immune genes (CIGs) and immune infiltration status of oral squamous cell carcinoma (OSCC) and Sjogrens syndrome (SS) in the transcriptional level by bioinformatics analysis to provide scientific basis for diagnosis and therapy of OSCC in SS patients. Methods  OSCC and SS datasets were downloaded from GEO database. The differentially expressed genes (DEGs) in OSCC and SS were screened by limma R package combined with Venn map, and then the CIGs were obtained by cross screening with immune gene datasets. Least absolute shrinkage and selection operator (LASSO) regression was used to screen core CIGs. The CIBERSORT R package was used to analyze the type and ratio of the infiltrated immune cells. Results  We screened 2 885 DEGs by OSCC dataset and 2 472 DEGs by SS dataset, then 55 CIGs were predicted via further intersecting with DEGs; second cross screening following LASSO regression analysis showed that RASGRP3 was a potential core CIG, and was upregulated in both OSCC and SS. Besides, immune infiltration of memory CD4⁺T cells, macrophage and activated natural killer (NK) cells were associated with RASGRP3 levels in OSCC and SS. Conclusions  The oncogene RASGRP3 can serve as a potential therapeutic target and biomarker for SS and OSCC. RASGRP3 was closely related to CD4⁺T cells, macrophage and activated NK cells, which might provide a new idea for exploring the immunotherapy strategy of OSCC for SS patients.

Key words: oral squamous cell carcinoma, Sjogren's syndrome, core cross immune genes, immune cells, immune infiltration, bioinformatics analysis