Type II nitric oxide synthase (NOS2) expression correlates with lymph nodestatus in oral squamous cell carcinoma

In tumour biology, nitric oxide (NO) has a complex array of concentration-d ependent actions, including both inhibitory and promoting effects. It is th ought that the levels of NO found in many human cancers lead to enhanced an giogenesis and tumour dissemination. In the current study, we assessed the immunohistochemical expression of the enzyme type II nitric oxide synthase (NOS2) in 41 cases of oral squamous cell carcinoma and correlated the findi ngs with lymph node status. A significant relationship was found between NO S2 expression and lymph node metastasis (P<0.0002). Furthermore, lymph node metastasis correlated with the degree and intensity of staining seen (P<0. 001). No correlation was found between the size of the primary tumour, degr ee of tumour differentiation or smoking status and NOS2 staining. Western b lotting confirmed NOS2 protein expression in select cases. As with many oth er human tumours, NOS2 is not a ubiquitous finding in oral cancer. Its expr ession may be of value in assessing lymph node status prior to surgery, and it represents a target for possible therapeutic manipulation.