The Clinical, Pathological, and Prognostic Value of High PD-1 Expression and the Presence of Epstein–Barr Virus Reactivation in Patients with Laryngeal Cancer

Simple Summary Our immune reaction depends on some ‘immune checkpoints’, such as PD-1, PD-L1 and CTLA4, that maintain homeostasis and define new pathways in the fight against carcinogenesis. Viral infections, including EBV (Epstein-Barr Virus) are one of the risk factors for laryngeal cancer. The aim of our study was to evaluate the level of PD-1 receptor in blood, tumor and lymph node samples collected from 45 laryngeal cancer patients and 20 healthy volunteers from control group. We detected the presence of EBV molecules in cancer samples and show the relationship between tumor progression and the level of PD-1 receptor. We confirmed, that EBV infection may affect the PD-1/PD-L1 pathway and develop the laryngeal cancer. What is important, the level of PD-1 on CD4+ T cells in lymph nodes increased the risk of death, so it can be an important prognostic factor (marker) for laryngeal cancer patients’ treatment and their prognosis. Abstract Due to the development of molecular diagnostic techniques, the latest research in the diagnosis of cancer diseases, including laryngeal cancer, has been focused on the occurrence of specific types of molecular patterns, including markers expressed on cells of the immune system (e.g., PD-1, PD-L1, and CTLA-4), which may be directly or indirectly involved in the development of neoplastic diseases. Laryngeal cancer is one of the diseases that is diagnosed more often in men than in women, and many factors are involved in its development, including environmental and lifestyle factors, viral infections (e.g., HPV, HHV-1, and EBV), and disorders of the immune system. In this study, we determined the level of PD-1 receptor expression on T and B lymphocytes and their relationships based on the classification of the grade and TNM scale, in turn based on blood, tumor, and lymph node samples from patients diagnosed with laryngeal cancer. In addition, we determined the presence of EBV genetic material in the tested biological materials as well as the degree of cancer advancement and its correlation with the level of PD-1 receptor expression. The results suggested that the level of PD-1 expression on T and B lymphocytes was significantly higher in the tumor samples as compared to the lymph node samples, and their comparison with the immunophenotype results from the blood samples provided statistically significant data on changes in the incidence of individual subpopulations of T and B lymphocytes and the level of PD-1 receptor expression. The analysis of the individual parameters of the TNM scale also showed significant changes between the PD-1 expression and the tested biological material in individual subgroups of the scale. We also found that the expression of PD-1 on the CD4+ T cells from the lymph node samples caused an almost 1.5-fold increase in the risk of death. In the analyses of the presence of EBV, the highest concentration was recorded in the tumor samples, then for the lymph node samples, and followed by the blood samples. Furthermore, we showed that the presence of EBV genetic material was positively correlated with the level of PD-1 expression in the tested biological materials.