Abstract: Objective To investigate the mRNA and protein expression of inducible nitric oxide synthase(iNOS) and its clinical significance in cutaneous malignant melanoma(MM).Methods The iNOS protein expression was detected in tissue sections from 30 MM patients using immunohistochemistry method.Reverse transcription polymerase chain reaction(RT-PCR) was used to measure the iNOS mRNA expression in MM tissues and adjacent normal tissues from 6 of the 30 MM patients.Results The positive rates of iNOS protein and mRNA were both significantly higher in tumorous samples than those in normal tissues(86.7% vs 20.0%,P=0.000; 4/6 vs 1/6,P=0.024).The positive rate of iNOS protein was 69.2% in MM without metastasis,significant lower than that(100%) in MM with metastasis.Conclusion The abnormal expression of iNOS may play an important role in the occurrence,development and metastasis of MM.

Key words: Melanoma, Nitric oxide synthase, Message RNA(mRNA)