Correlation between type II nitric oxide synthase and p53 expression in oral squamous cell carcinoma

Prolonged nitric oxide (NO) production by the enzyme type II nitric oxide synthase (NOS2) has been implicated in angiogenesis and metastasis of human cancers. In animal models, wild-type p53 (but not mutant) protein results in down-regulation of NOS2 expression, which reduces both tumour growth and dissemination. In the current study, we aimed to find out whether a correlation was present in oral squamous cell carcinoma. Fifty-six cases of squamous cell carcinoma were assessed immunohistochemically using antibodies to NOS2 and p53 (clone DO-7). We also confirmed NOS2 protein expression in selected cases using immunoblotting. The results were correlated with clinicopathological findings. Statistical analysis showed a significant relationship between p53 and NOS2 expression (P= 0.001). No relationship was found between size of tumour or histological degree of differentiation, and NOS2 expression in the primary tumour.