Expression of inducible nitric oxide synthase is increased in acute myeloid leukaemia.

Significant activity of inducible nitric oxide synthase (iNOS) has been reported in tumour cells, including chronic lymphoid leukaemic cells. In this study, we analysed the expression of iNOS in 15 untreated patients with acute myeloid leukaemia (AML) and in 7 normal controls. Using flow cytometry and immunocytochemistry, we demonstrated that patients with AML had a high expression of iNOS when compared to controls. There was no correlation between the expression of iNOS and the expression of p53 and K, H, and N-ras mutation and expression, suggesting that the high expression of iNOS is independent of these proteins and could be the result of transcription factors expressed in AML.