[The expression and clinical implication of inducible nitric oxide synthase mRNA in laryngeal carcinoma and hypopharyngeal carcinoma].

Objective: To study the expression of inducible nitric oxide synthase(iNOS) mRNA in laryngeal carcinoma and hypopharyngeal carcinoma and its clinical significance.
Method: The tissue samples (laryngeal carcinoma, 40; hypopharyngeal carcinoma, 12; adjacent tissue, 50; laryngeal papilloma, 10; amyloidosis of larynx, 2; and normal laryngeal mucosa, 7) were examined by reverse transcription-polymerase chain reaction(RT-PCR).
Result: 1. The target gene of iNOS were detected in 41 of 52 tumor tissues, 10 of 50 adjacent tissues, 5 of 12 benign tumor tissues and 0 of 7 normal tissues. The difference was significant (P < 0.0001, P < 0.005, P < 0.0001); 2. No significant difference was found among the expression of iNOSmRNA in different primary locations, there was significant statistical difference between the early clinical stages (T1-T2) and the advanced stages (T3-T4); 3. The poorly differentiated tumor cell showed a higher iNOSmRNA expression than that in moderate differentiated tumor cell (P < 0.05) and the iNOSmRNA expression in the lymph node metastasis group was higher than the non-metastasis group (P < 0.05).
Conclusion: It suggests that iNOS gene expression occurs in human laryngeal carcinoma and hypopharyngeal carcinoma, it might involve in the development of head and neck neoplasms in gene level by generating NO.