It is known that the relationship between pro-angiogenic and anti-angiogenic factors is responsible for the presence and intensity of neoangiogenesis. The angiogenic factors are produced by tumour cells and/or by tumour-infiltrating inflammatory cells such as macrophages or polymorphonuclear leukocytes (PMN). In the present study we compared VEGF secretion with IL-18 and NO release by PMN derived from oral cavity cancer patients. Knowledge of the relationship between mediators above could help in better understanding the role of PMN in angiogenesis in this patient group. The results from culture supernatants of PMN were confronted with the serum levels of parameters examined. We found an interesting relationship between VEGF and IL-18 concentrations in the culture supernatants of PMN derived from patients with oral cavity cancer. High production of VEGF was associated with low production of IL-18 by PMN derived from patients before treatment. During examinations after treatment we found lower concentrations of VEGF and higher concentrations of IL-18 than those in the study before treatment. In contrast to VEGF and IL-18, the NO production by PMN of cancer patients, before and after treatment, was unchanged. We also demonstrated markedly elevated serum levels of VEGF as well as IL-18 according to the progression of the disease. Results obtained indicate that relations between VEGF and IL-18 released by PMN may promote neoangiogenesis and may be important for benign tumour cells to acquire metastatic phenotype in the early stage of oral cavity cancer. Furthermore, our results suggest that the concentrations of VEGF and IL-18 in the serum are sensitive tumour markers in this patient group before and after treatment.