Objective: To determine the association between T-cell tumor-infiltrating lymphocytes and EBV load in tumor tissues of undifferentiated nasopharyngeal carcinoma.
Methods: Our study was conducted on 91 formalin-fixed paraffin-embedded tissue samples from patients with undifferentiated nasopharyngeal carcinoma at Hanoi Medical University Hospital. EBV load in tumor tissue was quantified by Real-time PCR. TILs were evaluated on Hematoxylin-Eosin stained sections. Among these samples, 30 samples were accessed T-cell expression via CD3 staining by immunohistochemistry and evaluated in the inner-tumor, outer-tumor, and whole-tumor.
Results: The mean age of the patients was 54.05 ± 13.39 years, and the EBV positive rate was 90.1%. TIL level 3 accounted for the highest proportion (42.9%), followed by level 2 (36.3%). EBV load differed significantly between the low- and high-TIL groups (p = 0.007). Among the T-cell expression group, EBV load in the tumors with CD3 low expression was higher than in tumors with CD3 high expression; the difference was statistically significant in the inner-tumor and whole-tumor, but not in the outer-tumor (p = 0.128).
Conclusion: High EBV load in nasopharyngeal carcinoma tissues with low CD3 expression suggests that immune escapes, such as T-cell attack, might boost EBV replication.