CD18 and CD36 expression in neutrophils from tumors and tumor-draining lymph nodes: implications for metastasis in oral squamous cell carcinoma.

BACKGROUND: Neutrophil infiltration in tumors and tumor-draining lymph nodes (TDLNs) influences oral squamous cell carcinoma (OSCC) progression and metastasis. Neutrophils can exhibit an immunosuppressive phenotype, with CD18 and CD36 potentially linked to this. This study characterizes CD18/CD36 expression on neutrophils from different OSCC microenvironments and their association with metastasis. METHODS: We assessed CD18 and CD36 expression on neutrophils from OSCC tumors, TDLNs, and healthy lymph nodes using flow cytometry. We also examined whether co-culture with the CAL27 oral cancer cell line influenced CD18/CD36 expression in blood neutrophils from healthy donors. RESULTS: Neutrophils from OSCC tumors and TDLNs exhibited higher CD18 expression than those from healthy lymph nodes, while CD36 was increased only in OSCC tumors. The highest CD18/CD36 expression was observed in metastasis. In vitro co-culture with CAL27 cells prolonged neutrophil survival and enhanced CD18 expression but had no impact on CD36 levels. CONCLUSION: Increased CD18/CD36 expression in OSCC neutrophils, particularly in metastasis, suggests their role in tumorigenesis. The elevated CD18 expression in TDLNs highlights enhanced neutrophil-lymphocyte interactions during cancer progression. Our in vitro findings underscore the ability of cancer cells to modulate neutrophil lifespan and phenotype, though this may not fully replicate the tumor microenvironment. This study provides insight into neutrophil contributions to OSCC progression and supports their potential as therapeutic targets.