BACKGROUND: The nitric oxide synthases (NOS) have been observed in humantumour cell lines as well as in solid tumours. Neuronal isoform of NOS (NOS1) was particularly abundantin low-differentiated gynaecological, breast and central nerve system tumours, suggesting that it maycharacterize poorly differentiated tumours. So far, little is known about expression of the neuronalNOS isoform in non-small cell lung cancer. Our aim was to compare NOS1 expression in non-small lung carcinomaswith respect to tumor staging and p53 protein expression.
MATERIAL AND METHODS: Thirty-two cases of non-smalllung carcinomas of all grades of malignancy and ten control lung specimens with neoplastic lesions wereexamined. Paraffin-embedded tissues were stained with hematoxylin and eosin, or with antibodies to NOS1and p53, and evaluated under light microscope.
RESULTS: No statistical correlation between expressionof p53, NOS1 and degree od tumour differentiation was observed.
CONCLUSION: Expression of NOS1 can notserve as a marker for highly malignant tumours in the non-small cell lung carcinomas.

Keywords: NOS1, granular pattern, perinuclear bead-like pattern, lung cancers