Infection pattern and immunological characteristics of Epstein-Barr virus latent infection in cervical squamous cell carcinoma

Previous studies reported the association between Epstein-Barr virus (EBV) and cervical squamous cell carcinoma (CSCC), but its infection pattern and clinical significance unclear. This study aimed to comprehensively investigate the infection pattern, clinicopathology, outcomes, and immunology of this entity in central China. We evaluated a total of 104 untreated CSCC tumor tissue specimens using in situ hybridization for EBV-encoded small RNAs (EBERs), and by employing flowcytometry fluorescence hybridization for human papillomavirus (HPV) genotyping. The expression of EBV latency proteins and immune biomarkers was evaluated and quantified by immunohistochemistry. EBERs transcripts were detected in 21 (20.2%) cases overall (in malignant epithelial cells of 13 cases and in lymphocytes of 8 cases). EBV belonged to latency type I infection in CSCC. The high-risk (HR)-HPV was detected in all of EBV-positive CSCC, and the difference of detection rate of HR-HPV was significant when compared with EBV-negative CSCC (p = 0.001). The specific clinicopathology with increased frequency of advanced clinical stages, tumor-positive lymph nodes, neural invasion, and increased infiltration depth (all p value < 0.05) were observed in cases with EBV. However, EBV infection was found to have no impact on prognosis of patients with CSCC. Increased densities of forkhead box P3 (FoxP3)(+)-tumor infiltrating lymphocytes (TILs) (p = 0.005) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4)(+)-TILs (p = 0.017) and higher expression of programmed cell death-1 (PD-1) (p = 0.002) and programmed cell death-1 ligand 1 (PD-L1) (p = 0.040) were associated with EBV latent infection in CSCC, and these immunological changes were more likely to be associated with the infection in lymphocytes rather than tumor cells. Moreover, in patients with HPV-positive CSCC, similar significant differences were still found. In conclusions, EBV-positive CSCC may have specific infection pattern and clinicopathology and can exhibit an immunosuppressive microenvironment dominated by Treg cells aggregation and immune checkpoint activation.