Background & objective: Transforming growth factor beta (TGF-beta) has various biological functions, and plays important roles in cell proliferation, differentiation and apoptosis. This study was to investigate the expression and clinical significance of TGF-beta1 and its signaling pathway proteins (TGF-beta1 receptors TGFbetaRI and TGFbetaRII, cytoplasmic mediator Smad4) in nasopharyngeal carcinoma (NPC).
Methods: The expression of TGF-beta1, TGFbetaRI, TGFbetaRII, and Smad4 in 91 specimens of NPC was detected by SP immunohistochemistry. Their correlations to local relapse, distant metastasis and survival rate of the patients were analyzed.
Results: The positive rates of TGF-beta1, TGFbetaRI, TGFbetaRII and Smad4 were 69.2%, 73.6%, 62.6% and 72.5% in NPC. The differences in the positive rates of TGF-beta1 (0, 12.7%, 50.8%, and 36.5%) and TGFbetaRII (0, 15.8%, 54.4%, and 29.8%) among stageI, II, III and IV NPC were significant (P<0.05). However, there was no significant difference in the expression of TGFbetaRI and Smad4. The local relapse rate was significantly higher and 5-year overall survival rate was significantly lower in TGF-beta1-positive patients than in TGF-beta1-negative patients (22.2% vs. 3.6%, P<0.05û 63.5% vs. 82.1%, P<0.05). All the 4 proteins had no correlation to the distant metastasis of NPC (P>0.05).
Conclusion: Autocrine TGF-beta1 exists in NPC patients, which is correlated to the local relapse and survival.