Abstract
INTRODUCTION AND AIMS: Oral squamous cell carcinoma (OSCC) is characterized by high aggressiveness and mortality, posing major challenges for patients and health care systems. Current diagnostic and therapeutic approaches-including surgery, radiotherapy, and chemotherapy-are often hindered by late diagnosis and poor prognosis. Therefore, identifying novel biomarkers is urgently needed to enhance early detection and inform treatment decisions. METHODS: This study evaluated the role of synaptophysin-like 1 (SYPL1) as a potential biomarker in OSCC using RNA sequencing data obtained from the UCSC XENA database and the Gene Expression Omnibus. Cox proportional hazards regression and Spearman correlation analyses were employed to evaluate the association between SYPL1 expression and clinical outcomes. Furthermore, SYPL1 expression levels in OSCC samples were confirmed using real-time polymerase chain reaction. RESULTS: SYPL1 was significantly upregulated in OSCC tissues, with an area under the curve of 0.654 for discriminating tumour from normal tissues. High SYPL1 expression correlated with poor prognosis, particularly in T3 and N0 stage patients. Immune infiltration analysis indicated a significant negative correlation between SYPL1 levels and cytotoxic and dendritic cells, suggesting a role in tumour immune modulation. The messenger RNA expressions of SYPL1 are increased in OSCC samples. CONCLUSION: SYPL1 demonstrates significant value as a diagnostic and prognostic biomarker in OSCC. A nomogram incorporating SYPL1 expression with clinical factors shows robust predictive performance for 1-, 3-, and 5-year survival probabilities. While these findings suggest a potential role in OSCC pathogenesis, the specific functional mechanisms of SYPL1-including its possible involvement in immune modulation or tumour progression-require further experimental validation to establish causal relationships. CLINICAL RELEVANCE: SYPL1 is significantly upregulated in OSCC tissues and shows potential as a diagnostic biomarker for distinguishing tumours from normal samples, particularly in early detection. Elevated SYPL1 expression is associated with poor prognosis in patients with OSCC, especially in T3 and N0 stages, suggesting that it could complement the TNM staging system for improved risk stratification. Mechanistically, the negative correlation between SYPL1 expression and infiltrating cytotoxic and dendritic cells implies a possible role in immune modulation, but this requires functional validation. Future studies should focus on elucidating the functional mechanisms of SYPL1 to assess its therapeutic relevance.