Because existing studies assessing plasma TNF-α concentration did not give conclusive results, we suggest that genetic predispositions such as SNP of its gene (it may potentially affect both expression level and activity of encoded protein and is much more stable than the cytokine level—highly dynamic and multi-factor dependent, produced by both tumour tissues and by normal cells in reaction to different damaging factors) may be a better predictor of OM as well as prognostic factor in patients irradiated due to HNC. This evidence concerns the gene TNF and neoplasm.