Background: The immune profile in primary resected hypopharyngeal squamous cell carcinoma (HPSCC) and its prognostic value remain to be defined.
Methods: We enrolled 100 patients with HPSCC underwent primary surgical resection at our department. HPSCC samples were examined using immunohistochemistry for the expressions of CD8, Foxp3, CD163, CD66B, programmed death ligand-1 (PD-L1), and interferon (IFN)-γ. The immune pattern of the tumor microenvironment (TME) was discriminated into inflamed and non-inflamed tumors based on the presence or absence of parenchymal CD8+ T cells.
Results: We found that 74% of HPSCC cases in our cohort were characterized by an immune-inflamed TME. Immune-inflamed patterns demonstrated an inferior survival with a significantly increased density of CD163+ tumor-associated macrophages and Foxp3+ regulatory T cells. Additionally, the inflamed tumor showed increased expression of PD-L1, without IFN-γ upregulation.
Conclusions: The immune-inflamed pattern is the predominant preexisting immune phenotype in HPSCC and demonstrates immunosuppressive immune cell recruitment.
Keywords: Hypopharyngeal carcinoma; Immunoscore; programmed death ligand-1; squamous cell carcinoma; tumor immune microenvironment.
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