The relationship between TNF-α gene promoter polymorphism (- 1211 T > C), the plasma concentration of TNF-α, and risk of oral mucositis and shortening of overall survival in patients subjected to intensity-modulated radiation therapy due to head and neck cancer.

ABSTRACT

PURPOSE: Radiotherapy (RTH) usually combined with chemotherapy (C-RTH) is the main method of treatment in head and neck cancer (HNC). The most common complication of RTH is oral mucositis (OM). At a certain stage of RTH, it occurs in almost all patients, often lead to discontinuation of treatment. Tumour necrosis factor alpha (TNF-α) is a cytokine secreted during inflammatory process accompanying RTH and the development of cancer itself. Single nucleotide polymorphism (SNP) of the TNF-α promoter region can potentially affect the function or expression of this cytokine, and thus modulate the risk of occurrence and intensity of OM and shortening of overall survival (OS). METHODS: The study group consisted of 62 patients with HNC in whom intensity-modulated radiation therapy (IMRT) technique was applied. The plasma TNF-α level was assessed using the ELISA Kit. Genotyping was performed using a real-time PCR method. RESULTS: HNC patients with the CC genotype of TNF-α (- 1211 T > C) have higher TNF-α plasma concentrations than those with T allele (10.70 vs 9.62 ng/ml). Patients with the 3rd degree of OM have significantly higher TNF-α levels after 5th (10.40 vs 9.45 ng/ml) and 7th (10.32 vs 9.60 ng/ml) week of RTH. CC genotype was related to a higher risk of 3rd degree OM development in the last weeks of RTH (5th, OR = 7.33; 7th, OR = 23.15). CONCLUSIONS: High TNF-α plasma concentration and CC genotype of TNF-α are related to the higher risk of more severe OM in patients irradiated due to HNC. High TNF-α plasma concentration and CC genotype of TNF-α are independent prognostic factors for patients subjected to RTH due to HNC.