Prognostic significance of PD-1, CTLA-4, CD4, and CD8 expression in olfactory neuroblastoma

There are limited data regarding immune surveillance mechanisms in olfactory neuroblastoma. We investigated the expression of programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), CD4, and CD8 in olfactory neuroblastoma to identify potential therapeutic targets. Immunohistochemistry was used to detect PD-1 and CTLA-4 and measure the numbers of CD4⁺ and CD8⁺ T cells in 56 patients with olfactory neuroblastoma. The relationships between these molecules in tumor microenvironment, clinicopathological features, and survival were analyzed. The prevalence of PD-1 in Kadish C stage was 24.14%, significantly greater than in Kadish A and B stage. CD4⁺ T-cell and CD8⁺ T-cell levels correlated with higher Hyams histological grade and Kadish stage. In addition, PD-1 was related positively with CTLA-4, CD4⁺ T cells, and CD8⁺ T cells in olfactory neuroblastoma. Univariate survival analysis showed that higher PD-1 positivity, CD8⁺ T cells, and Hyams grade correlated with worse clinical outcome. Multivariate analysis showed that the expression of PD-1 was an independent parameter for poor prognosis. In conclusion, olfactory neuroblastoma with PD-1 expression had more aggressive clinicopathological features and worse prognosis. PD-1 may potentially predict the outcome of olfactory neuroblastoma patients.