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.