Rta-IgG as a biomarker for diagnosis and post treatment prognostic of nasopharyngeal carcinoma.

Background: Nasopharyngeal carcinoma (NPC) is a common type of head and neck cancer.

Objective: This study aimed to detect the expression of Epstein-Barr viral Rta protein in patients with untreated NPC, and compare the serum Rta-IgG with the VCA-IgA in patients with NPC.

Methods: In the current work, the nasopharyngeal tissues of untreated NPC patients (n= 13) and non-NPC controls (n= 10) were collected for the immunohistochemical (IHC) staining to analyze the levels of Rta protein expression, meanwhile serum samples from the participants were prepared to assess the roles of Rta-IgG level with Enzyme-linked immunosorbence assay (ELISA) in diagnosis of NPC including the patients with NPC, the patients with other cancers, and normal volunteers.

Results: The levels of serum Rta-IgG in 26 NPC patients were monitored at pre- and post-treatments, as well as one to two year after. We found that there was a significant difference of the expression levels of Rta protein between NPC and non-NPC groups (P< 0.05). Correspondingly, the levels of serum Rta-IgG in NPC patients (3.05, 1.19-4.95) were significantly higher than those of non-NPC participants (0.15, 0.08-0.30, P< 0.05) including the patients with lung cancer (0.14, 0.08-0.19), the patients with breast carcinoma (0.17, 0.10-0.25), the patients with gastric carcinoma (0.08, 0.05-0.16), the patients with malignant lymphoma (0.13, 0.08-0.20), the patients with benign nasopharyngeal disease (1.65, 0.74-1.93) and healthy volunteers (0.22, 0.13-0.32), respectively. With a receiver operation characteristic (ROC) analysis, the cut-off value to discriminate NPC patients from the controls was established at 0.92 (S/CO) for Rta-IgG (sensitivity 83.6%; specificity 82.4%), the diagnosis efficacy of Rta-IgG was higher than VCA-IgA. The positive rates of Rta-IgG were related to clinical stage, but not metastatic sites. Serum concentrations of Rta-IgG were decreased in NPC patients with effective radiation, and slightly raised or with no change with ineffective radiation.

Conclusions: Rta expression levels are elevated in the patients with NPC, and serum Rta-IgG is a promising biomarker in both differential diagnosis and therapy-monitoring of the patients with NPC.