Background & objective: Recently, most of studies have indicated that nitric oxide (NO) plays an important role in carcinogenesis and tumor progression. Inducible nitric oxide synthase(iNOS) has been found at significantly higher expression levels in head and neck squamous cell carcinoma (HNSCCA) specimens as compared with that in normal tissue. Furthermore, these data provided strong evidance for the role of iNOS generating NO in HNSCCA progression. However, there was no report about whether expression of iNOS mRNA in oral carcinoma is associated with its biological behavior. This study was designed to investigate the correlation between expression of inducible nitric oxide synthase mRNA (iNOS mRNA) in squamous cell carcinoma of tongue tissue and its invasive growth, neck lymph node metastasis, and prognosis.
Methods: Sixty-eight cases with squamous cell carcinoma of tongue tissues were investigated. All cases with tongue carcinoma were followed up to obtain the information of prognosis. In situ hybridization assay was used to detect the expression of iNOS mRNA in tongue carcinoma tissues. The correlation between expression of iNOS mRNA in squamous cell carcinoma of tongue tissue and its invasive growth, neck lymph node metastasis, and prognosis was analyzed.
Results: 1. The positive expression rate of iNOS mRNA was 86.1% and 48.0% in the group of invasive growth and no invasive growth respectively. The difference between the two groups was significant with coefficient of 0.3. 2. The positive expression rate of iNOS mRNA was 85.7% and 62.5% in the group of positive lymph node metastasis and negative lymph node metastasis respectively. The difference between the two groups was significant, which the correlation coefficient was 0.3. 3. Three-year survival rate was significantly lower in the group of positive expression of iNOS mRNA than that in the group of negative expression of iNOS mRNA in the tongue carcinoma.
Conclusions: 1. A positive correlation was found between the positive expression of iNOS mRNA and invasive growth as well as neck lymph node metastatsis of squamous cell carcinoma of tongue. 2. The patient's prognosis of the positive expression of iNOS mRNA would be worse than that of the negative expression of iNOS mRNA in tongue carcinoma tissue.