Inducible nitric oxide synthase: correlation with extracapsular spread and enhancement of tumor cell invasion in head and neck squamous cell carcinoma.
BACKGROUND
Extracapsular nodal spread is a major prognostic indicator in head and neck cancer. Nitric oxide (NO), primarily produced by the enzyme inducible NO synthase (iNOS), has a large number of actions in cancer biology, but no studies have investigated its possible role in extracapsular spread or tumor invasion.


METHODS
Immunochemistry was used to study iNOS expression in 48 patients with either extracapsular or encapsulated metastasis. In vitro invasion assays were performed using H357 (an oral squamous cell carcinoma cell line) using the iNOS inhibitor drug, 1400 W.


RESULTS
iNOS expression was significantly associated with extracapsular spread, with 22/27 cases showing positive iNOS expression compared with 8/21 cases in the encapsulated group (p = .01). Invasion of H357 cells was inhibited by 1400 W at concentrations of 100 microM and 1 mM (p = .002, p = .003).


CONCLUSIONS
iNOS protein seems to be associated with extracapsular spread and invasion in head and neck cancer. Further studies are required to understand this role more fully.
Department of Maxillofacial Head and Neck Surgery, Queen Alexandra Hospital, Portsmouth PO6 3LY, United Kingdom. peter.brennan@porthosp.nhs.uk
Peter A
PA
Brennan
Simon
S
Dennis
David
D
Poller
Marisol
M
Quintero
Roberto
R
Puxeddu
Gareth J
GJ
Thomas
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D006258:Head and Neck Neoplasms / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D052247:Nitric Oxide Synthase Type II