Abstract: Objective:To investigate the cell heterogeneity and the effects of tertiary lymphatic structure (TLS) on the number and functions of immune cells in oral squamous cell carcinoma (OSCC), establish the immune cell atlas of OSCC and dissect the roles of TLS in the pathogenesis of OSCC. Methods:Based on the single cell RNA sequencing data from the primary diagnosed OSCC patients, we used the bioinformatics methods and tools to perform dimension reduction, cell clustering and annotation. Differences of the immune cell composition and internal molecular characteristics in TLS-/+ patients were compared and analyzed. R programming language and R packages were used to perform data analysis and visualize the results. Results:Heterogeneous immune cell populations existed in OSCC patients, including typical immune cell populations; The proportion of immune cells in TLS+ patients were significantly increased and the T cells of TLS+ patients were enriched in pathways related to T cell differentiation, T cell activation and signal transduction. Furthermore, differences analysis of monocyte/macrophages revealed that the interferon signal response and cytokine product were enhanced in TLS+ patients. Conclusions:Heterogeneous immune cell populations existed in OSCC patients and significant molecular differences of these immune cells were dissected between TLS+ and TLS- patients, which could play important roles in exploring the pathogenesis, prognosis and potential targeted therapies of OSCC.

Key words: OSCC, Single-cell RNA sequencing, TLS, Immune cells, Bioinformatics analysis